diff --git a/changelog.d/0-release-notes/WPB-20728 b/changelog.d/0-release-notes/WPB-20728
new file mode 100644
index 0000000000..24d528fbf8
--- /dev/null
+++ b/changelog.d/0-release-notes/WPB-20728
@@ -0,0 +1,15 @@
+Background-worker configuration: required values when supplying your own Helm values
+
+Add the following fields under `background-worker`:
+
+- `config.domain`
+- `config.postgresql`
+- `config.cassandraBrig`
+- `config.cassandraGalley`
+- `secrets.pgPassword`
+
+Notes
+- `config.cassandra` (for gundeck) already exists; no change needed.
+- `config.backgroundJobs` and `config.postgresqlPool` have defaults; override only if needed.
+- `config.postgresMigration.conversation` defaults to `postgresql`; change only if migrating conversations to PostgreSQL.
+- `config.brig` and `config.gundeck` endpoints have in-cluster defaults; override only if your service DNS/ports differ.
diff --git a/changelog.d/2-features/WPB-20728 b/changelog.d/2-features/WPB-20728
new file mode 100644
index 0000000000..24cbff570d
--- /dev/null
+++ b/changelog.d/2-features/WPB-20728
@@ -0,0 +1 @@
+Add users of user groups to a channel in asynchronous background worker job
diff --git a/charts/background-worker/README.md b/charts/background-worker/README.md
index 55e379a4ed..b3ef345c5f 100644
--- a/charts/background-worker/README.md
+++ b/charts/background-worker/README.md
@@ -1,5 +1,21 @@
-Note that background-worker depends on some provisioned storage, namely:
+Note that background-worker depends on some provisioned storage/services, namely:
 
 - rabbitmq
+- postgresql
+- cassandra (three clusters)
+
+PostgreSQL configuration
+- Set connection parameters under `config.postgresql` (libpq keywords: `host`, `port`, `user`, `dbname`, etc.).
+- Provide the password via `secrets.pgPassword`; it is mounted at `/etc/wire/background-worker/secrets/pgPassword` and referenced from the configmap.
+
+Cassandra configuration
+- Background-worker connects to three Cassandra clusters:
+  - `config.cassandra` (keyspace: `gundeck`) for the dead user notification watcher.
+  - `config.cassandraBrig` (keyspace: `brig`) for the user store.
+  - `config.cassandraGalley` (keyspace: `galley`) for conversation-related data access.
+- TLS may be configured via either a reference (`tlsCaSecretRef`) or inline CA (`tlsCa`) for each cluster. Secrets mount under:
+  - `/etc/wire/background-worker/cassandra-gundeck`
+  - `/etc/wire/background-worker/cassandra-brig`
+  - `/etc/wire/background-worker/cassandra-galley`
 
 These are dealt with independently from this chart.
diff --git a/charts/background-worker/templates/_helpers.tpl b/charts/background-worker/templates/_helpers.tpl
index 96bf8dd1b8..ec6e25f5f4 100644
--- a/charts/background-worker/templates/_helpers.tpl
+++ b/charts/background-worker/templates/_helpers.tpl
@@ -8,18 +8,38 @@
   {{- (semverCompare ">= 1.24-0" (include "kubeVersion" .)) -}}
 {{- end -}}
 
-{{- define "useCassandraTLS" -}}
+{{- define "useGundeckCassandraTLS" -}}
 {{ or (hasKey .cassandra "tlsCa") (hasKey .cassandra "tlsCaSecretRef") }}
 {{- end -}}
 
-{{/* Return a Dict of TLS CA secret name and key
-This is used to switch between provided secret (e.g. by cert-manager) and
-created one (in case the CA is provided as PEM string.)
-*/}}
-{{- define "tlsSecretRef" -}}
+{{- define "useBrigCassandraTLS" -}}
+{{ or (hasKey .cassandraBrig "tlsCa") (hasKey .cassandraBrig "tlsCaSecretRef") }}
+{{- end -}}
+
+{{- define "useGalleyCassandraTLS" -}}
+{{ or (hasKey .cassandraGalley "tlsCa") (hasKey .cassandraGalley "tlsCaSecretRef") }}
+{{- end -}}
+
+{{- define "gundeckTlsSecretRef" -}}
 {{- if .cassandra.tlsCaSecretRef -}}
 {{ .cassandra.tlsCaSecretRef | toYaml }}
 {{- else }}
-{{- dict "name" "background-worker-cassandra" "key" "ca.pem" | toYaml -}}
+{{- dict "name" "background-worker-cassandra-gundeck" "key" "ca.pem" | toYaml -}}
+{{- end -}}
+{{- end -}}
+
+{{- define "brigTlsSecretRef" -}}
+{{- if .cassandraBrig.tlsCaSecretRef -}}
+{{ .cassandraBrig.tlsCaSecretRef | toYaml }}
+{{- else }}
+{{- dict "name" "background-worker-cassandra-brig" "key" "ca.pem" | toYaml -}}
+{{- end -}}
+{{- end -}}
+
+{{- define "galleyTlsSecretRef" -}}
+{{- if and .cassandraGalley .cassandraGalley.tlsCaSecretRef -}}
+{{ .cassandraGalley.tlsCaSecretRef | toYaml }}
+{{- else }}
+{{- dict "name" "background-worker-cassandra-galley" "key" "ca.pem" | toYaml -}}
 {{- end -}}
 {{- end -}}
diff --git a/charts/background-worker/templates/cassandra-secret.yaml b/charts/background-worker/templates/cassandra-secret.yaml
index d5d9c61dfc..158d75ea54 100644
--- a/charts/background-worker/templates/cassandra-secret.yaml
+++ b/charts/background-worker/templates/cassandra-secret.yaml
@@ -1,9 +1,9 @@
-{{/* Secret for the provided Cassandra TLS CA. */}}
+{{/* Secrets for provided Cassandra TLS CAs */}}
 {{- if not (empty .Values.config.cassandra.tlsCa) }}
 apiVersion: v1
 kind: Secret
 metadata:
-  name: background-worker-cassandra
+  name: background-worker-cassandra-gundeck
   labels:
     app: background-worker
     chart: {{ .Chart.Name }}-{{ .Chart.Version | replace "+" "_" }}
@@ -13,3 +13,33 @@ type: Opaque
 data:
   ca.pem: {{ .Values.config.cassandra.tlsCa | b64enc | quote }}
 {{- end }}
+{{- if not (empty .Values.config.cassandraBrig.tlsCa) }}
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  name: background-worker-cassandra-brig
+  labels:
+    app: background-worker
+    chart: {{ .Chart.Name }}-{{ .Chart.Version | replace "+" "_" }}
+    release: "{{ .Release.Name }}"
+    heritage: "{{ .Release.Service }}"
+type: Opaque
+data:
+  ca.pem: {{ .Values.config.cassandraBrig.tlsCa | b64enc | quote }}
+{{- end }}
+{{- if and .Values.config.cassandraGalley (not (empty .Values.config.cassandraGalley.tlsCa)) }}
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  name: background-worker-cassandra-galley
+  labels:
+    app: background-worker
+    chart: {{ .Chart.Name }}-{{ .Chart.Version | replace "+" "_" }}
+    release: "{{ .Release.Name }}"
+    heritage: "{{ .Release.Service }}"
+type: Opaque
+data:
+  ca.pem: {{ .Values.config.cassandraGalley.tlsCa | b64enc | quote }}
+{{- end }}
diff --git a/charts/background-worker/templates/configmap.yaml b/charts/background-worker/templates/configmap.yaml
index 1a0e37e609..b2521c72f0 100644
--- a/charts/background-worker/templates/configmap.yaml
+++ b/charts/background-worker/templates/configmap.yaml
@@ -21,15 +21,43 @@ data:
       host: federator
       port: 8080
 
+    brig:
+      host: brig
+      port: 8080
+
+    gundeck:
+      host: gundeck
+      port: 8080
+
     cassandra:
       endpoint:
         host: {{ .cassandra.host }}
         port: 9042
       keyspace: gundeck
-      {{- if eq (include "useCassandraTLS" .) "true" }}
-      tlsCa: /etc/wire/background-worker/cassandra/{{- (include "tlsSecretRef" . | fromYaml).key }}
+      {{- if eq (include "useGundeckCassandraTLS" .) "true" }}
+      tlsCa: /etc/wire/background-worker/cassandra-gundeck/{{- (include "gundeckTlsSecretRef" . | fromYaml).key }}
+      {{- end }}
+
+    cassandraBrig:
+      endpoint:
+        host: {{ .cassandraBrig.host }}
+        port: 9042
+      keyspace: brig
+      {{- if eq (include "useBrigCassandraTLS" .) "true" }}
+      tlsCa: /etc/wire/background-worker/cassandra-brig/{{- (include "brigTlsSecretRef" . | fromYaml).key }}
       {{- end }}
 
+    cassandraGalley:
+      endpoint:
+        host: {{ .cassandraGalley.host }}
+        port: 9042
+      keyspace: galley
+      {{- if eq (include "useGalleyCassandraTLS" .) "true" }}
+      tlsCa: /etc/wire/background-worker/cassandra-galley/{{- (include "galleyTlsSecretRef" . | fromYaml).key }}
+      {{- end }}
+
+    domain: {{ .Values.domain }}
+
     {{- with .rabbitmq }}
     rabbitmq:
       host: {{ .host }}
@@ -48,4 +76,18 @@ data:
 
     backendNotificationPusher:
 {{toYaml .backendNotificationPusher | indent 6 }}
+    {{- with .backgroundJobs }}
+    backgroundJobs:
+{{ toYaml . | indent 6 }}
+    {{- end }}
+    postgresql:
+{{ toYaml .postgresql | indent 6 }}
+    {{- if hasKey $.Values.secrets "pgPassword" }}
+    postgresqlPassword: /etc/wire/background-worker/secrets/pgPassword
+    {{- end }}
+    postgresqlPool:
+{{ toYaml .postgresqlPool | nindent 6 }}
+    {{- if .postgresMigration }}
+    postgresMigration: {{- toYaml .postgresMigration | nindent 6 }}
+    {{- end }}
   {{- end }}
diff --git a/charts/background-worker/templates/deployment.yaml b/charts/background-worker/templates/deployment.yaml
index aeeab1ecc5..c159ee7335 100644
--- a/charts/background-worker/templates/deployment.yaml
+++ b/charts/background-worker/templates/deployment.yaml
@@ -39,10 +39,20 @@ spec:
         - name: "background-worker-secrets"
           secret:
             secretName: "background-worker"
-        {{- if eq (include "useCassandraTLS" .Values.config) "true" }}
-        - name: "background-worker-cassandra"
+        {{- if eq (include "useGundeckCassandraTLS" .Values.config) "true" }}
+        - name: "background-worker-cassandra-gundeck"
           secret:
-            secretName: {{ (include "tlsSecretRef" .Values.config | fromYaml).name }}
+            secretName: {{ (include "gundeckTlsSecretRef" .Values.config | fromYaml).name }}
+        {{- end }}
+        {{- if eq (include "useBrigCassandraTLS" .Values.config) "true" }}
+        - name: "background-worker-cassandra-brig"
+          secret:
+            secretName: {{ (include "brigTlsSecretRef" .Values.config | fromYaml).name }}
+        {{- end }}
+        {{- if eq (include "useGalleyCassandraTLS" .Values.config) "true" }}
+        - name: "background-worker-cassandra-galley"
+          secret:
+            secretName: {{ (include "galleyTlsSecretRef" .Values.config | fromYaml).name }}
         {{- end }}
         {{- if .Values.config.rabbitmq.tlsCaSecretRef }}
         - name: "rabbitmq-ca"
@@ -58,11 +68,21 @@ spec:
             {{- toYaml .Values.podSecurityContext | nindent 12 }}
         {{- end }}
           volumeMounts:
+          - name: "background-worker-secrets"
+            mountPath: "/etc/wire/background-worker/secrets"
           - name: "background-worker-config"
             mountPath: "/etc/wire/background-worker/conf"
-          {{- if eq (include "useCassandraTLS" .Values.config) "true" }}
-          - name: "background-worker-cassandra"
-            mountPath: "/etc/wire/background-worker/cassandra"
+          {{- if eq (include "useGundeckCassandraTLS" .Values.config) "true" }}
+          - name: "background-worker-cassandra-gundeck"
+            mountPath: "/etc/wire/background-worker/cassandra-gundeck"
+          {{- end }}
+          {{- if eq (include "useBrigCassandraTLS" .Values.config) "true" }}
+          - name: "background-worker-cassandra-brig"
+            mountPath: "/etc/wire/background-worker/cassandra-brig"
+          {{- end }}
+          {{- if eq (include "useGalleyCassandraTLS" .Values.config) "true" }}
+          - name: "background-worker-cassandra-galley"
+            mountPath: "/etc/wire/background-worker/cassandra-galley"
           {{- end }}
           {{- if .Values.config.rabbitmq.tlsCaSecretRef }}
           - name: "rabbitmq-ca"
diff --git a/charts/background-worker/templates/secret.yaml b/charts/background-worker/templates/secret.yaml
index 25a22ce67e..dfde355db9 100644
--- a/charts/background-worker/templates/secret.yaml
+++ b/charts/background-worker/templates/secret.yaml
@@ -15,4 +15,7 @@ data:
   {{- with .Values.secrets }}
   rabbitmqUsername: {{ .rabbitmq.username | b64enc | quote }}
   rabbitmqPassword: {{ .rabbitmq.password | b64enc | quote }}
+  {{- if .pgPassword }}
+  pgPassword: {{ .pgPassword | b64enc | quote }}
+  {{- end }}
   {{- end }}
diff --git a/charts/background-worker/values.yaml b/charts/background-worker/values.yaml
index a0117c9363..2eb0058944 100644
--- a/charts/background-worker/values.yaml
+++ b/charts/background-worker/values.yaml
@@ -19,6 +19,22 @@ config:
   logLevel: Info
   logFormat: StructuredJSON
   enableFederation: false # keep in sync with brig, cargohold and galley charts' config.enableFederation as well as wire-server chart's tags.federation
+  # Postgres connection settings
+  #
+  # Values are described in https://www.postgresql.org/docs/17/libpq-connect.html#LIBPQ-PARAMKEYWORDS
+  # To set the password via a background-worker secret see `secrets.pgPassword`.
+  #
+  # Below is an example configuration used in CI tests.
+  postgresql:
+    host: postgresql # DNS name without protocol
+    port: "5432"
+    user: wire-server
+    dbname: wire-server
+  postgresqlPool:
+    size: 100
+    acquisitionTimeout: 10s
+    agingTimeout: 1d
+    idlenessTimeout: 10m
   rabbitmq:
     host: rabbitmq
     port: 5672
@@ -29,15 +45,37 @@ config:
     # tlsCaSecretRef:
     #   name: <secret-name>
     #   key: <ca-attribute>
+  # Cassandra clusters used by background-worker
   cassandra:
     host: aws-cassandra
+  cassandraBrig:
+    host: aws-cassandra
+  cassandraGalley:
+    host: aws-cassandra
 
   backendNotificationPusher:
     pushBackoffMinWait: 10000 # in microseconds, so 10ms
     pushBackoffMaxWait: 300000000 # microseconds, so 300s
     remotesRefreshInterval: 300000000 # microseconds, so 300s
 
-secrets: {}
+  # Background jobs consumer configuration
+  backgroundJobs:
+    # Maximum number of in-flight jobs per process
+    concurrency: 8
+    # Per-attempt timeout in seconds
+    jobTimeout: 60
+    # Total attempts, including the first try
+    maxAttempts: 3
+
+  domain: example.org
+
+  # Controls where conversation data is stored/accessed
+  postgresMigration:
+    conversation: postgresql
+
+secrets:
+  {}
+  # pgPassword: <postgres-password>
 
 podSecurityContext:
   allowPrivilegeEscalation: false
diff --git a/charts/integration/templates/configmap.yaml b/charts/integration/templates/configmap.yaml
index 84aa623acb..5402a048f2 100644
--- a/charts/integration/templates/configmap.yaml
+++ b/charts/integration/templates/configmap.yaml
@@ -56,6 +56,11 @@ data:
     backgroundWorker:
       host: backgroundWorker.{{ .Release.Namespace }}.svc.cluster.local
       port: 8080
+      # Background jobs defaults for integration tests
+      backgroundJobs:
+        concurrency: 4
+        jobTimeout: 5
+        maxAttempts: 3
 
     stern:
       host: stern.{{ .Release.Namespace }}.svc.cluster.local
diff --git a/docs/src/developer/reference/config-options.md b/docs/src/developer/reference/config-options.md
index 5ca0820dca..5812d9dd5f 100644
--- a/docs/src/developer/reference/config-options.md
+++ b/docs/src/developer/reference/config-options.md
@@ -1707,3 +1707,43 @@ gundeck:
   settings:
     cellsEventQueue: "cells_events"
 ```
+## Background worker: Background jobs
+
+The background worker consumes jobs from RabbitMQ to process tasks asynchronously. The following configuration controls the consumer’s behavior:
+
+Internal YAML file and Helm values (under `background-worker.config`):
+
+```yaml
+backgroundJobs:
+  # Maximum number of in-flight jobs per process
+  concurrency: 8
+  # Per-attempt timeout in seconds
+  jobTimeout: 60
+  # Total attempts including the first run
+  maxAttempts: 3
+```
+
+Notes:
+
+- `concurrency` controls the AMQP prefetch and caps parallel handler execution per process.
+- `jobTimeout` bounds each attempt; timed‑out attempts are retried until `maxAttempts` is reached.
+- `maxAttempts` is total tries (first run plus retries). On final failure, the job is dropped (NACK requeue=false) and counted in metrics.
+
+Additional background-worker configuration:
+
+```yaml
+# Cassandra clusters
+cassandra:
+  host: aws-cassandra
+cassandraBrig:
+  host: aws-cassandra
+cassandraGalley:
+  host: aws-cassandra
+
+# Conversation storage backend selection
+postgresMigration:
+  conversation: cassandra # or postgresql
+```
+
+- `cassandraGalley` configures the third Cassandra cluster used for conversation-related data; TLS may be configured via `tlsCa` or `tlsCaSecretRef` similarly to the other clusters.
+- `postgresMigration.conversation` selects the storage location for conversation data; aligns with galley’s option and defaults to `cassandra`.
diff --git a/hack/helm_vars/wire-server/values.yaml.gotmpl b/hack/helm_vars/wire-server/values.yaml.gotmpl
index f675fc761f..07016b143e 100644
--- a/hack/helm_vars/wire-server/values.yaml.gotmpl
+++ b/hack/helm_vars/wire-server/values.yaml.gotmpl
@@ -58,6 +58,7 @@ brig:
       teamCreatorWelcome: https://teams.wire.com/login
       teamMemberWelcome: https://wire.com/download
       accountPages: https://account.wire.com
+    # Background-worker uses Brig's Cassandra keyspace.
     cassandra:
       host: {{ .Values.cassandraHost }}
       replicaCount: 1
@@ -604,6 +605,11 @@ background-worker:
       pushBackoffMinWait: 1000 # 1ms
       pushBackoffMaxWait: 500000 # 0.5s
       remotesRefreshInterval: 1000000 # 1s
+    backgroundJobs:
+      concurrency: 8
+      jobTimeout: 60
+      maxAttempts: 3
+    # Cassandra clusters used by background-worker
     cassandra:
       host: {{ .Values.cassandraHost }}
       replicaCount: 1
@@ -612,6 +618,23 @@ background-worker:
           name: "cassandra-jks-keystore"
           key: "ca.crt"
       {{- end }}
+    cassandraBrig:
+      host: {{ .Values.cassandraHost }}
+      replicaCount: 1
+      {{- if .Values.useK8ssandraSSL.enabled }}
+      tlsCaSecretRef:
+          name: "cassandra-jks-keystore"
+          key: "ca.crt"
+      {{- end }}
+    cassandraGalley:
+      host: {{ .Values.cassandraHost }}
+      replicaCount: 1
+      {{- if .Values.useK8ssandraSSL.enabled }}
+      tlsCaSecretRef:
+          name: "cassandra-jks-keystore"
+          key: "ca.crt"
+      {{- end }}
+    domain: {{ .Values.domain }}
     rabbitmq:
       port: 5671
       adminPort: 15671
@@ -620,10 +643,16 @@ background-worker:
       tlsCaSecretRef:
         name: "rabbitmq-certificate"
         key: "ca.crt"
+    postgresql:
+      host: "postgresql"
+      port: "5432"
+      user: wire-server
+      dbname: wire-server
   secrets:
     rabbitmq:
       username: {{ .Values.rabbitmqUsername }}
       password: {{ .Values.rabbitmqPassword }}
+    pgPassword: "posty-the-gres"
 
 integration:
   ingress:
diff --git a/hack/helmfile.yaml.gotmpl b/hack/helmfile.yaml.gotmpl
index 2fe0dc9791..f3aba0bcb0 100644
--- a/hack/helmfile.yaml.gotmpl
+++ b/hack/helmfile.yaml.gotmpl
@@ -18,6 +18,7 @@ environments:
       - imagePullPolicy: Always
       - storageClass: hcloud-volumes
       - cassandraHost: cassandra-ephemeral
+      - domain: example.org
       - useK8ssandraSSL:
           enabled: false
       - elasticsearch:
@@ -30,6 +31,7 @@ environments:
       - imagePullPolicy: Always
       - storageClass: hcloud-volumes
       - cassandraHost: k8ssandra-cluster-datacenter-1-service
+      - domain: example.org
       - useK8ssandraSSL:
           enabled: true
       - elasticsearch:
@@ -42,6 +44,7 @@ environments:
       - imagePullPolicy: Never
       - storageClass: standard
       - cassandraHost: cassandra-ephemeral
+      - domain: example.org
       - useK8ssandraSSL:
           enabled: false
       - elasticsearch:
@@ -54,6 +57,7 @@ environments:
       - imagePullPolicy: Never
       - storageClass: standard
       - cassandraHost: k8ssandra-cluster-datacenter-1-service
+      - domain: example.org
       - useK8ssandraSSL:
           enabled: true
       - elasticsearch:
diff --git a/integration/test/Test/Events.hs b/integration/test/Test/Events.hs
index 52021e5edf..fac210a115 100644
--- a/integration/test/Test/Events.hs
+++ b/integration/test/Test/Events.hs
@@ -157,11 +157,12 @@ testTemporaryQueuesAreDeletedAfterUse = do
         aliceClientQueue = Queue {name = fromString aliceClientQueueName, vhost = fromString beResource.berVHost}
         deadNotifsQueue = Queue {name = fromString "dead-user-notifications", vhost = fromString beResource.berVHost}
         cellsEventsQueue = Queue {name = fromString "cells_events", vhost = fromString beResource.berVHost}
+        backgroundJobsQueue = Queue {name = fromString "background-jobs", vhost = fromString beResource.berVHost}
 
     -- Wait for queue for the new client to be created
     eventually $ do
       queuesBeforeWS <- rabbitmqAdmin.listQueuesByVHost (fromString beResource.berVHost) (fromString "") True 100 1
-      queuesBeforeWS.items `shouldMatchSet` [deadNotifsQueue, cellsEventsQueue, aliceClientQueue]
+      queuesBeforeWS.items `shouldMatchSet` [deadNotifsQueue, cellsEventsQueue, aliceClientQueue, backgroundJobsQueue]
 
     runCodensity (createEventsWebSocket alice Nothing) $ \ws -> do
       handle <- randomHandle
@@ -169,7 +170,7 @@ testTemporaryQueuesAreDeletedAfterUse = do
 
       queuesDuringWS <- rabbitmqAdmin.listQueuesByVHost (fromString beResource.berVHost) (fromString "") True 100 1
       addJSONToFailureContext "queuesDuringWS" queuesDuringWS $ do
-        length queuesDuringWS.items `shouldMatchInt` 4
+        length queuesDuringWS.items `shouldMatchInt` 5
 
       -- We cannot use 'assertEvent' here because there is a race between the temp
       -- queue being created and rabbitmq fanning out the previous events.
@@ -183,7 +184,7 @@ testTemporaryQueuesAreDeletedAfterUse = do
 
     eventually $ do
       queuesAfterWS <- rabbitmqAdmin.listQueuesByVHost (fromString beResource.berVHost) (fromString "") True 100 1
-      queuesAfterWS.items `shouldMatchSet` [deadNotifsQueue, cellsEventsQueue, aliceClientQueue]
+      queuesAfterWS.items `shouldMatchSet` [deadNotifsQueue, cellsEventsQueue, aliceClientQueue, backgroundJobsQueue]
 
 testSendMessageNoReturnToSenderWithConsumableNotificationsProteus :: (HasCallStack) => App ()
 testSendMessageNoReturnToSenderWithConsumableNotificationsProteus = do
diff --git a/integration/test/Test/UserGroup.hs b/integration/test/Test/UserGroup.hs
index 4e34207c1c..9bee467b69 100644
--- a/integration/test/Test/UserGroup.hs
+++ b/integration/test/Test/UserGroup.hs
@@ -6,7 +6,7 @@ import API.Brig
 import API.Galley
 import API.GalleyInternal (setTeamFeatureLockStatus)
 import Control.Error (lastMay)
-import Notifications (isUserGroupCreatedNotif, isUserGroupUpdatedNotif)
+import Notifications (isMemberJoinNotif, isUserGroupCreatedNotif, isUserGroupUpdatedNotif)
 import SetupHelpers
 import Testlib.Prelude
 
@@ -396,22 +396,11 @@ testUserGroupRemovalOnDelete = do
 
 testUserGroupUpdateChannelsSucceeds :: (HasCallStack) => App ()
 testUserGroupUpdateChannelsSucceeds = do
-  (alice, tid, [_bob]) <- createTeam OwnDomain 2
+  (alice, tid, _) <- createTeam OwnDomain 1
   setTeamFeatureLockStatus alice tid "channels" "unlocked"
-  let config =
-        object
-          [ "status" .= "enabled",
-            "config"
-              .= object
-                [ "allowed_to_create_channels" .= "team-members",
-                  "allowed_to_open_channels" .= "team-members"
-                ]
-          ]
-  setTeamFeatureConfig alice tid "channels" config >>= assertSuccess
+  setTeamFeatureConfig alice tid "channels" channelsConfig >>= assertSuccess
 
-  ug <-
-    createUserGroup alice (object ["name" .= "none", "members" .= (mempty :: [String])])
-      >>= getJSON 200
+  ug <- createUserGroup alice (object ["name" .= "none", "members" .= (mempty :: [String])]) >>= getJSON 200
   gid <- ug %. "id" & asString
 
   convs <- replicateM 5 $ postConversation alice (defMLS {team = Just tid, groupConvType = Just "channel"}) >>= getJSON 201 >>= objConvId
@@ -424,7 +413,8 @@ testUserGroupUpdateChannelsSucceeds = do
 
   bindResponse (getUserGroupWithChannels alice gid) $ \resp -> do
     resp.status `shouldMatchInt` 200
-    (resp.json %. "channels" >>= asList >>= traverse objQid) `shouldMatchSet` for (take 2 convs) objQid
+    actual <- resp.json %. "channels" >>= asList >>= traverse objQid
+    actual `shouldMatchSet` for (take 2 convs) objQid
 
   bindResponse (getUserGroups alice (def {includeChannels = True})) $ \resp -> do
     resp.status `shouldMatchInt` 200
@@ -446,10 +436,6 @@ testUserGroupUpdateChannelsSucceeds = do
     resp.status `shouldMatchInt` 200
     (resp.json %. "channels" >>= fmap length . asList) `shouldMatchInt` 0
 
-  bindResponse (getUserGroups alice (def {includeChannels = True})) $ \resp -> do
-    resp.status `shouldMatchInt` 200
-    (resp.json %. "page.0.channels" >>= fmap length . asList) `shouldMatchInt` 0
-
 testUserGroupUpdateChannelsNonAdmin :: (HasCallStack) => App ()
 testUserGroupUpdateChannelsNonAdmin = do
   (alice, tid, [bob]) <- createTeam OwnDomain 2
@@ -495,3 +481,81 @@ testUserGroupUpdateChannelsNonChannel = do
       >>= getJSON 201
       >>= objConvId
   updateUserGroupChannels alice gid [convId.id_] >>= assertLabel 404 "user-group-channel-not-found"
+
+testUserGroupAddUsersToGroupWithChannels :: (HasCallStack) => App ()
+testUserGroupAddUsersToGroupWithChannels = do
+  (alice, tid, mems@[bob, charlie, dave, eve, franzi]) <- createTeam OwnDomain 6
+  setTeamFeatureLockStatus alice tid "channels" "unlocked"
+  setTeamFeatureConfig alice tid "channels" channelsConfig >>= assertSuccess
+
+  [bobId, charlieId, daveId, eveId, franziId] <- for mems $ asString . (%. "id")
+
+  -- Create user group with bob as initial member
+  ug <- createUserGroup alice (object ["name" .= "test group", "members" .= [bobId]]) >>= getJSON 200
+  gid <- ug %. "id" & asString
+
+  -- Create two conversations (channels) for the team
+  [convId1, convId2] <- replicateM 2 $ postConversation alice (defMLS {team = Just tid, groupConvType = Just "channel"}) >>= getJSON 201 >>= objConvId
+
+  -- Associate both channels with the user group
+  withWebSocket bob $ \bobWs -> do
+    updateUserGroupChannels alice gid [convId1.id_, convId2.id_] >>= assertSuccess
+    replicateM_ 2 $ awaitMatch isMemberJoinNotif bobWs
+
+  for_ [convId1, convId2] $ \convId -> do
+    bindResponse (getConversation alice convId) $ \resp -> do
+      resp.status `shouldMatchInt` 200
+      members <- resp.json %. "members" %. "others" >>= asList
+      memberIds <- mapM ((%. "qualified_id") >=> (%. "id") >=> asString) members
+      memberIds `shouldMatchSet` [bobId]
+
+  -- Add charlie, dave, and eve to the group using addUsersToGroup
+  withWebSockets [charlie, dave, eve] $ \wss -> do
+    addUsersToGroup alice gid [charlieId, daveId, eveId] >>= assertSuccess
+    for_ wss $ replicateM_ 2 . awaitMatch isMemberJoinNotif
+
+  -- Verify all three users are now in the first channel
+  for_ [convId1, convId2] $ \convId -> do
+    bindResponse (getConversation alice convId) $ \resp -> do
+      resp.status `shouldMatchInt` 200
+      members <- resp.json %. "members" %. "others" >>= asList
+      memberIds <- mapM ((%. "qualified_id") >=> (%. "id") >=> asString) members
+      memberIds `shouldMatchSet` [bobId, charlieId, daveId, eveId]
+
+    -- now we make charlie and dave admins in the conversation
+    updateConversationMember alice convId charlie "wire_admin" >>= assertSuccess
+    updateConversationMember alice convId dave "wire_admin" >>= assertSuccess
+
+    bindResponse (getConversation alice convId) $ \resp -> do
+      resp.status `shouldMatchInt` 200
+      members <- resp.json %. "members" %. "others" >>= asList
+      actual <- for members toIdRolePair
+      let expected = [(bobId, "wire_member"), (charlieId, "wire_admin"), (daveId, "wire_admin"), (eveId, "wire_member")]
+      actual `shouldMatchSet` expected
+
+  -- when we now add another user, we expect roles not be overwritten
+  withWebSockets [franzi] $ \wss -> do
+    addUsersToGroup alice gid [franziId] >>= assertSuccess
+    for_ wss $ replicateM_ 2 . awaitMatch isMemberJoinNotif
+
+  for_ [convId1] $ \convId -> do
+    bindResponse (getConversation alice convId) $ \resp -> do
+      resp.status `shouldMatchInt` 200
+      members <- resp.json %. "members" %. "others" >>= asList
+      actual <- for members toIdRolePair
+      let expected = [(bobId, "wire_member"), (charlieId, "wire_admin"), (daveId, "wire_admin"), (eveId, "wire_member"), (franziId, "wire_member")]
+      actual `shouldMatchSet` expected
+  where
+    toIdRolePair :: Value -> App (String, String)
+    toIdRolePair mem = (,) <$> (mem %. "qualified_id.id" & asString) <*> (mem %. "conversation_role" & asString)
+
+channelsConfig :: Value
+channelsConfig =
+  object
+    [ "status" .= "enabled",
+      "config"
+        .= object
+          [ "allowed_to_create_channels" .= "team-members",
+            "allowed_to_open_channels" .= "team-members"
+          ]
+    ]
diff --git a/libs/polysemy-wire-zoo/polysemy-wire-zoo.cabal b/libs/polysemy-wire-zoo/polysemy-wire-zoo.cabal
index 42d0ef800a..87dc102d65 100644
--- a/libs/polysemy-wire-zoo/polysemy-wire-zoo.cabal
+++ b/libs/polysemy-wire-zoo/polysemy-wire-zoo.cabal
@@ -33,6 +33,7 @@ library
     Wire.Sem.Paging.Cassandra
     Wire.Sem.Random
     Wire.Sem.Random.IO
+    Wire.Sem.Random.Null
 
   other-modules:      Paths_polysemy_wire_zoo
   hs-source-dirs:     src
diff --git a/libs/polysemy-wire-zoo/src/Wire/Sem/Random.hs b/libs/polysemy-wire-zoo/src/Wire/Sem/Random.hs
index 8cc1ef3386..20e6d02466 100644
--- a/libs/polysemy-wire-zoo/src/Wire/Sem/Random.hs
+++ b/libs/polysemy-wire-zoo/src/Wire/Sem/Random.hs
@@ -21,6 +21,7 @@ module Wire.Sem.Random
   ( Random (..),
     bytes,
     uuid,
+    newId,
     scimTokenId,
     liftRandom,
     nDigitNumber,
@@ -28,7 +29,7 @@ module Wire.Sem.Random
 where
 
 import Crypto.Random.Types
-import Data.Id (ScimTokenId)
+import Data.Id (Id, ScimTokenId)
 import Data.UUID (UUID)
 import Imports
 import Polysemy
@@ -36,6 +37,7 @@ import Polysemy
 data Random m a where
   Bytes :: Int -> Random m ByteString
   Uuid :: Random m UUID
+  NewId :: Random m (Id a)
   ScimTokenId :: Random m ScimTokenId
   LiftRandom :: (forall mr. (MonadRandom mr) => mr a) -> Random m a
   NDigitNumber :: Int -> Random m Integer
diff --git a/libs/polysemy-wire-zoo/src/Wire/Sem/Random/IO.hs b/libs/polysemy-wire-zoo/src/Wire/Sem/Random/IO.hs
index d073d267e8..53d75a904e 100644
--- a/libs/polysemy-wire-zoo/src/Wire/Sem/Random/IO.hs
+++ b/libs/polysemy-wire-zoo/src/Wire/Sem/Random/IO.hs
@@ -35,6 +35,7 @@ randomToIO ::
 randomToIO = interpret $ \case
   Bytes i -> embed $ randBytes i
   Uuid -> embed $ UUID.nextRandom
+  NewId -> embed $ randomId @IO
   ScimTokenId -> embed $ randomId @IO
   LiftRandom m -> embed @IO $ m
   NDigitNumber n -> embed $ randIntegerZeroToNMinusOne (10 ^ n)
diff --git a/libs/polysemy-wire-zoo/src/Wire/Sem/Random/Null.hs b/libs/polysemy-wire-zoo/src/Wire/Sem/Random/Null.hs
new file mode 100644
index 0000000000..7d19eff66c
--- /dev/null
+++ b/libs/polysemy-wire-zoo/src/Wire/Sem/Random/Null.hs
@@ -0,0 +1,39 @@
+-- This file is part of the Wire Server implementation.
+--
+-- Copyright (C) 2025 Wire Swiss GmbH <opensource@wire.com>
+--
+-- This program is free software: you can redistribute it and/or modify it under
+-- the terms of the GNU Affero General Public License as published by the Free
+-- Software Foundation, either version 3 of the License, or (at your option) any
+-- later version.
+--
+-- This program is distributed in the hope that it will be useful, but WITHOUT
+-- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+-- FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+-- details.
+--
+-- You should have received a copy of the GNU Affero General Public License along
+-- with this program. If not, see <https://www.gnu.org/licenses/>.
+
+module Wire.Sem.Random.Null
+  ( randomToNull,
+  )
+where
+
+import Crypto.Random
+import Data.Id (Id (..))
+import qualified Data.UUID as UUID
+import Imports
+import Polysemy
+import Wire.Sem.Random (Random (..))
+
+randomToNull ::
+  Sem (Random ': r) a ->
+  Sem r a
+randomToNull = interpret $ \case
+  Bytes i -> pure $ mconcat $ replicate i "0"
+  Uuid -> pure UUID.nil
+  NewId -> pure $ Id UUID.nil
+  ScimTokenId -> pure $ Id UUID.nil
+  LiftRandom m -> pure $ fst $ withDRG (drgNewSeed $ seedFromInteger 0) m
+  NDigitNumber n -> pure $ 10 ^ n
diff --git a/libs/types-common/src/Data/Id.hs b/libs/types-common/src/Data/Id.hs
index ebd24fc53b..ad7f4526ff 100644
--- a/libs/types-common/src/Data/Id.hs
+++ b/libs/types-common/src/Data/Id.hs
@@ -37,6 +37,7 @@ module Data.Id
     ServiceId,
     TeamId,
     ScimTokenId,
+    JobId,
     parseIdFromText,
     idToText,
     idObjectSchema,
@@ -111,6 +112,7 @@ data IdTag
   | OAuthClient
   | OAuthRefreshToken
   | Challenge
+  | Job
 
 idTagName :: IdTag -> Text
 idTagName Asset = "Asset"
@@ -125,6 +127,7 @@ idTagName ScimToken = "ScimToken"
 idTagName OAuthClient = "OAuthClient"
 idTagName OAuthRefreshToken = "OAuthRefreshToken"
 idTagName Challenge = "Challenge"
+idTagName Job = "Job"
 
 class KnownIdTag (t :: IdTag) where
   idTagValue :: IdTag
@@ -151,6 +154,8 @@ instance KnownIdTag 'OAuthClient where idTagValue = OAuthClient
 
 instance KnownIdTag 'OAuthRefreshToken where idTagValue = OAuthRefreshToken
 
+instance KnownIdTag 'Job where idTagValue = Job
+
 type AssetId = Id 'Asset
 
 type InvitationId = Id 'Invitation
@@ -177,6 +182,8 @@ type OAuthRefreshTokenId = Id 'OAuthRefreshToken
 
 type ChallengeId = Id 'Challenge
 
+type JobId = Id 'Job
+
 -- Id -------------------------------------------------------------------------
 
 data NoId = NoId deriving (Eq, Show, Generic)
@@ -434,6 +441,9 @@ newtype RequestId = RequestId
       ToBytes
     )
 
+instance Arbitrary RequestId where
+  arbitrary = RequestId . UUID.toASCIIBytes <$> arbitrary @UUID
+
 defRequestId :: (IsString s) => s
 defRequestId = "N/A"
 
diff --git a/libs/wire-api/src/Wire/API/BackgroundJobs.hs b/libs/wire-api/src/Wire/API/BackgroundJobs.hs
new file mode 100644
index 0000000000..c5a638cb1a
--- /dev/null
+++ b/libs/wire-api/src/Wire/API/BackgroundJobs.hs
@@ -0,0 +1,169 @@
+{-# LANGUAGE StrictData #-}
+{-# LANGUAGE TemplateHaskell #-}
+
+-- This file is part of the Wire Server implementation.
+--
+-- Copyright (C) 2025 Wire Swiss GmbH <opensource@wire.com>
+--
+-- This program is free software: you can redistribute it and/or modify it under
+-- the terms of the GNU Affero General Public License as published by the Free
+-- Software Foundation, either version 3 of the License, or (at your option) any
+-- later version.
+--
+-- This program is distributed in the hope that it will be useful, but WITHOUT
+-- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+-- FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+-- details.
+--
+-- You should have received a copy of the GNU Affero General Public License along
+-- with this program. If not, see <https://www.gnu.org/licenses/>.
+
+module Wire.API.BackgroundJobs where
+
+import Control.Arrow ((&&&))
+import Control.Lens (makePrisms)
+import Data.Aeson qualified as Aeson
+import Data.Id
+import Data.Map.Strict qualified as Map
+import Data.OpenApi qualified as S
+import Data.Schema
+import Imports
+import Network.AMQP qualified as Q
+import Network.AMQP.Types qualified as QT
+import Wire.Arbitrary (Arbitrary (..), GenericUniform (..))
+
+data JobPayload
+  = JobSyncUserGroupAndChannel SyncUserGroupAndChannel
+  | JobSyncUserGroup SyncUserGroup
+  deriving stock (Eq, Show, Generic)
+  deriving (Arbitrary) via GenericUniform JobPayload
+
+jobPayloadLabel :: JobPayload -> Text
+jobPayloadLabel p = case jobPayloadTag p of
+  JobSyncUserGroupAndChannelTag -> "sync-user-group-and-channel"
+  JobSyncUserGroupTag -> "sync-user-group"
+
+data JobPayloadTag
+  = JobSyncUserGroupAndChannelTag
+  | JobSyncUserGroupTag
+  deriving stock (Eq, Ord, Bounded, Enum, Show, Generic)
+  deriving (Arbitrary) via GenericUniform JobPayloadTag
+
+instance ToSchema JobPayloadTag where
+  schema =
+    enum @Text "JobPayloadTag" $
+      mconcat
+        [ element "sync-user-group-and-channel" JobSyncUserGroupAndChannelTag,
+          element "sync-user-group" JobSyncUserGroupTag
+        ]
+
+jobPayloadTag :: JobPayload -> JobPayloadTag
+jobPayloadTag =
+  \case
+    JobSyncUserGroupAndChannel {} -> JobSyncUserGroupAndChannelTag
+    JobSyncUserGroup {} -> JobSyncUserGroupTag
+
+jobPayloadTagSchema :: ObjectSchema SwaggerDoc JobPayloadTag
+jobPayloadTagSchema = field "type" schema
+
+data SyncUserGroupAndChannel = SyncUserGroupAndChannel
+  { teamId :: TeamId,
+    userGroupId :: UserGroupId,
+    convId :: ConvId,
+    actor :: UserId
+  }
+  deriving (Show, Eq, Generic)
+  deriving (Aeson.ToJSON, Aeson.FromJSON) via (Schema SyncUserGroupAndChannel)
+  deriving (Arbitrary) via GenericUniform SyncUserGroupAndChannel
+
+instance ToSchema SyncUserGroupAndChannel where
+  schema =
+    object "SyncUserGroupAndChannel" $
+      SyncUserGroupAndChannel
+        <$> (.teamId) .= field "team_id" schema
+        <*> (.userGroupId) .= field "user_group_id" schema
+        <*> (.convId) .= field "conv_id" schema
+        <*> (.actor) .= field "actor" schema
+
+data SyncUserGroup = SyncUserGroup
+  { teamId :: TeamId,
+    userGroupId :: UserGroupId,
+    actor :: UserId
+  }
+  deriving (Show, Eq, Generic)
+  deriving (Aeson.ToJSON, Aeson.FromJSON) via (Schema SyncUserGroup)
+  deriving (Arbitrary) via GenericUniform SyncUserGroup
+
+instance ToSchema SyncUserGroup where
+  schema =
+    object "SyncUserGroup" $
+      SyncUserGroup
+        <$> (.teamId) .= field "team_id" schema
+        <*> (.userGroupId) .= field "user_group_id" schema
+        <*> (.actor) .= field "actor" schema
+
+makePrisms ''JobPayload
+
+jobPayloadObjectSchema :: ObjectSchema SwaggerDoc JobPayload
+jobPayloadObjectSchema =
+  snd
+    <$> (jobPayloadTag &&& id)
+      .= bind
+        (fst .= jobPayloadTagSchema)
+        (snd .= dispatch jobPayloadDataSchema)
+  where
+    jobPayloadDataSchema :: JobPayloadTag -> ObjectSchema SwaggerDoc JobPayload
+    jobPayloadDataSchema = \case
+      JobSyncUserGroupAndChannelTag -> tag _JobSyncUserGroupAndChannel (field "payload" schema)
+      JobSyncUserGroupTag -> tag _JobSyncUserGroup (field "payload" schema)
+
+instance ToSchema JobPayload where
+  schema = object "JobPayload" jobPayloadObjectSchema
+
+deriving via (Schema JobPayload) instance Aeson.FromJSON JobPayload
+
+deriving via (Schema JobPayload) instance Aeson.ToJSON JobPayload
+
+deriving via (Schema JobPayload) instance S.ToSchema JobPayload
+
+-- | Background job envelope. Payload is a free-form JSON object.
+data Job = Job
+  { jobId :: JobId,
+    requestId :: RequestId,
+    payload :: JobPayload
+  }
+  deriving stock (Eq, Show, Generic)
+  deriving (Arbitrary) via GenericUniform Job
+  deriving (Aeson.ToJSON, Aeson.FromJSON, S.ToSchema) via Schema Job
+
+instance ToSchema Job where
+  schema =
+    object "Job" $
+      Job
+        <$> jobId .= field "id" schema
+        <*> requestId .= field "requestId" schema
+        <*> payload .= field "payload" schema
+
+backgroundJobsRoutingKey :: Text
+backgroundJobsRoutingKey = backgroundJobsQueueName
+
+backgroundJobsQueueName :: Text
+backgroundJobsQueueName = "background-jobs"
+
+ensureBackgroundJobsQueue :: Q.Channel -> IO ()
+ensureBackgroundJobsQueue chan = do
+  let headers =
+        QT.FieldTable
+          ( Map.fromList
+              [ ("x-queue-type", QT.FVString "quorum")
+              ]
+          )
+      q =
+        Q.newQueue
+          { Q.queueName = backgroundJobsQueueName,
+            Q.queueDurable = True,
+            Q.queueAutoDelete = False,
+            Q.queueExclusive = False,
+            Q.queueHeaders = headers
+          }
+  void $ Q.declareQueue chan q
diff --git a/libs/wire-api/src/Wire/API/Conversation.hs b/libs/wire-api/src/Wire/API/Conversation.hs
index 7e326d8daf..c9442d728c 100644
--- a/libs/wire-api/src/Wire/API/Conversation.hs
+++ b/libs/wire-api/src/Wire/API/Conversation.hs
@@ -74,6 +74,7 @@ module Wire.API.Conversation
     -- * invite
     Invite (..),
     InviteQualified (..),
+    InviteQualifiedInternal (..),
 
     -- * update
     ConversationRename (..),
@@ -249,6 +250,9 @@ instance ToSchema (Versioned 'V2 ConversationMetadata) where
           "ConversationMetadata"
           (conversationMetadataObjectSchema accessRolesSchemaV2)
 
+instance HasCellsState ConversationMetadata where
+  getCellsState = cnvmCellsState
+
 -- | Public-facing conversation type. Represents information that a
 -- particular user is allowed to see.
 --
@@ -268,6 +272,9 @@ data OwnConversation = OwnConversation
   deriving (Arbitrary) via (GenericUniform OwnConversation)
   deriving (FromJSON, ToJSON, S.ToSchema) via Schema OwnConversation
 
+instance HasCellsState OwnConversation where
+  getCellsState = getCellsState . cnvMetadata
+
 cnvType :: OwnConversation -> ConvType
 cnvType = cnvmType . cnvMetadata
 
@@ -1095,6 +1102,21 @@ instance ToSchema InviteQualified where
         <$> (.users) .= field "qualified_users" (nonEmptyArray schema)
         <*> roleName .= (fromMaybe roleNameWireAdmin <$> optField "conversation_role" schema)
 
+data InviteQualifiedInternal = InviteQualifiedInternal
+  { actor :: UserId,
+    invite :: InviteQualified
+  }
+  deriving stock (Eq, Show, Generic)
+  deriving (Arbitrary) via (GenericUniform InviteQualifiedInternal)
+  deriving (ToJSON, FromJSON, S.ToSchema) via (Schema InviteQualifiedInternal)
+
+instance ToSchema InviteQualifiedInternal where
+  schema =
+    object "InviteQualifiedInternal" $
+      InviteQualifiedInternal
+        <$> (.actor) .= field "actor" schema
+        <*> (.invite) .= field "invite" schema
+
 --------------------------------------------------------------------------------
 -- update
 
diff --git a/libs/wire-api/src/Wire/API/Conversation/CellsState.hs b/libs/wire-api/src/Wire/API/Conversation/CellsState.hs
index 10b6d12ec3..5ecee42ae8 100644
--- a/libs/wire-api/src/Wire/API/Conversation/CellsState.hs
+++ b/libs/wire-api/src/Wire/API/Conversation/CellsState.hs
@@ -76,3 +76,12 @@ cellsStateToInt32 = \case
   CellsDisabled -> 0
   CellsPending -> 1
   CellsReady -> 2
+
+class HasCellsState a where
+  getCellsState :: a -> CellsState
+
+instance HasCellsState CellsState where
+  getCellsState = id
+
+instance HasCellsState () where
+  getCellsState = def
diff --git a/libs/wire-api/src/Wire/API/Event/Conversation.hs b/libs/wire-api/src/Wire/API/Event/Conversation.hs
index 13fc23ce5b..1c620be050 100644
--- a/libs/wire-api/src/Wire/API/Event/Conversation.hs
+++ b/libs/wire-api/src/Wire/API/Event/Conversation.hs
@@ -33,6 +33,7 @@ module Wire.API.Event.Conversation
     CellsEventType (..),
     CellsEventData (..),
     cellsEventType,
+    shouldPushToCells,
 
     -- * Event lenses
     _EdMembersJoin,
@@ -92,6 +93,7 @@ import Test.QuickCheck qualified as QC
 import URI.ByteString ()
 import Wire.API.Conversation hiding (AddPermissionUpdate)
 import Wire.API.Conversation qualified as Conv
+import Wire.API.Conversation.CellsState
 import Wire.API.Conversation.Code (ConversationCode (..), ConversationCodeInfo)
 import Wire.API.Conversation.Protocol (ProtocolUpdate (unProtocolUpdate))
 import Wire.API.Conversation.Protocol qualified as P
@@ -581,6 +583,13 @@ instance ToJSONObject CellsEvent where
       A.Object o -> KeyMap.delete "data" o
       _ -> KeyMap.fromList []
 
+shouldPushToCells :: (HasCellsState a) => a -> Event -> Bool
+shouldPushToCells st e =
+  isCellsConversationEvent (evtType e) && case getCellsState st of
+    CellsDisabled -> False
+    CellsPending -> True
+    CellsReady -> True
+
 --------------------------------------------------------------------------------
 -- MultiVerb instances
 
diff --git a/libs/wire-api/test/unit/Test/Wire/API/Roundtrip/Aeson.hs b/libs/wire-api/test/unit/Test/Wire/API/Roundtrip/Aeson.hs
index 57cf9e9fda..91f136c22b 100644
--- a/libs/wire-api/test/unit/Test/Wire/API/Roundtrip/Aeson.hs
+++ b/libs/wire-api/test/unit/Test/Wire/API/Roundtrip/Aeson.hs
@@ -27,6 +27,7 @@ import Test.Tasty qualified as T
 import Test.Tasty.QuickCheck (Arbitrary, counterexample, testProperty, (.&&.), (===))
 import Type.Reflection (typeRep)
 import Wire.API.Asset qualified as Asset
+import Wire.API.BackgroundJobs qualified as BackgroundJobs
 import Wire.API.Call.Config qualified as Call.Config
 import Wire.API.Connection qualified as Connection
 import Wire.API.Conversation qualified as Conversation
@@ -356,7 +357,8 @@ tests =
       testRoundTrip @TeamsIntra.TeamStatus,
       testRoundTrip @TeamsIntra.TeamStatusUpdate,
       testRoundTrip @TeamsIntra.TeamData,
-      testRoundTrip @TeamsIntra.TeamName
+      testRoundTrip @TeamsIntra.TeamName,
+      testRoundTrip @BackgroundJobs.Job
     ]
 
 testRoundTrip ::
@@ -365,7 +367,7 @@ testRoundTrip ::
   T.TestTree
 testRoundTrip = testProperty msg trip
   where
-    msg = show (typeRep @a)
+    msg = show (typeRep @a) <> " JSON roundtrip"
     trip (v :: a) =
       counterexample (show $ toJSON v) $
         Right v === (parseEither parseJSON . toJSON) v
diff --git a/libs/wire-api/wire-api.cabal b/libs/wire-api/wire-api.cabal
index c7e39ed4ca..690725bb16 100644
--- a/libs/wire-api/wire-api.cabal
+++ b/libs/wire-api/wire-api.cabal
@@ -72,6 +72,7 @@ library
     Wire.API.App
     Wire.API.ApplyMods
     Wire.API.Asset
+    Wire.API.BackgroundJobs
     Wire.API.Bot
     Wire.API.Bot.Service
     Wire.API.Call.Config
diff --git a/libs/wire-subsystems/default.nix b/libs/wire-subsystems/default.nix
index 498d21aa2f..5a6c8b98e0 100644
--- a/libs/wire-subsystems/default.nix
+++ b/libs/wire-subsystems/default.nix
@@ -84,7 +84,9 @@
 , servant
 , servant-client-core
 , servant-server
+, singletons
 , sodium-crypto-sign
+, ssl-util
 , statistics
 , stomp-queue
 , string-conversions
@@ -191,7 +193,9 @@ mkDerivation {
     servant
     servant-client-core
     servant-server
+    singletons
     sodium-crypto-sign
+    ssl-util
     statistics
     stomp-queue
     template
@@ -292,7 +296,9 @@ mkDerivation {
     servant
     servant-client-core
     servant-server
+    singletons
     sodium-crypto-sign
+    ssl-util
     statistics
     stomp-queue
     string-conversions
diff --git a/services/galley/src/Galley/Effects/BackendNotificationQueueAccess.hs b/libs/wire-subsystems/src/Wire/BackendNotificationQueueAccess.hs
similarity index 97%
rename from services/galley/src/Galley/Effects/BackendNotificationQueueAccess.hs
rename to libs/wire-subsystems/src/Wire/BackendNotificationQueueAccess.hs
index fee78987c2..bbf37bbd29 100644
--- a/services/galley/src/Galley/Effects/BackendNotificationQueueAccess.hs
+++ b/libs/wire-subsystems/src/Wire/BackendNotificationQueueAccess.hs
@@ -1,4 +1,4 @@
-module Galley.Effects.BackendNotificationQueueAccess where
+module Wire.BackendNotificationQueueAccess where
 
 import Data.Qualified
 import Imports
diff --git a/libs/wire-subsystems/src/Wire/BackendNotificationQueueAccess/RabbitMq.hs b/libs/wire-subsystems/src/Wire/BackendNotificationQueueAccess/RabbitMq.hs
new file mode 100644
index 0000000000..41ed987515
--- /dev/null
+++ b/libs/wire-subsystems/src/Wire/BackendNotificationQueueAccess/RabbitMq.hs
@@ -0,0 +1,99 @@
+{-# LANGUAGE NumericUnderscores #-}
+
+module Wire.BackendNotificationQueueAccess.RabbitMq
+  ( interpretBackendNotificationQueueAccess,
+    Env (..),
+  )
+where
+
+import Control.Monad.Catch
+import Control.Retry
+import Data.Domain
+import Data.Id
+import Data.Qualified
+import Imports
+import Network.AMQP qualified as Q
+import Polysemy
+import Polysemy.Error
+import System.Logger qualified as Log
+import UnliftIO
+import Wire.API.Federation.BackendNotifications
+import Wire.API.Federation.Error
+import Wire.BackendNotificationQueueAccess (BackendNotificationQueueAccess (..))
+
+data Env = Env
+  { channelMVar :: (MVar (Q.Channel)),
+    logger :: Log.Logger,
+    local :: Local (),
+    requestId :: RequestId
+  }
+
+interpretBackendNotificationQueueAccess ::
+  (Member (Embed IO) r) =>
+  Maybe Env ->
+  Sem (BackendNotificationQueueAccess ': r) a ->
+  Sem r a
+interpretBackendNotificationQueueAccess mEnv = interpret $ \case
+  EnqueueNotification deliveryMode remote action -> runError do
+    env <- note FederationNotConfigured mEnv
+    embed $ enqueueSingleNotification env (tDomain remote) deliveryMode action
+  EnqueueNotificationsConcurrently m xs rpc -> runError do
+    env <- note FederationNotConfigured mEnv
+    embed $ enqueueNotificationsConcurrently env m xs rpc
+  EnqueueNotificationsConcurrentlyBuckets m xs rpc -> runError do
+    env <- note FederationNotConfigured mEnv
+    embed $ enqueueNotificationsConcurrentlyBuckets env m xs rpc
+
+enqueueSingleNotification :: Env -> Domain -> Q.DeliveryMode -> FedQueueClient c a -> IO a
+enqueueSingleNotification env remoteDomain deliveryMode action = do
+  let ownDomain = tDomain env.local
+  let policy = limitRetries 3 <> constantDelay 1_000_000
+      handlers =
+        skipAsyncExceptions
+          <> [logRetries (const $ pure True) logError]
+  recovering policy handlers (const $ go ownDomain)
+  where
+    logError willRetry (SomeException e) status = do
+      Log.err env.logger $
+        Log.msg @Text "failed to enqueue notification in RabbitMQ"
+          . Log.field "error" (displayException e)
+          . Log.field "willRetry" willRetry
+          . Log.field "retryCount" status.rsIterNumber
+          . Log.field "request" env.requestId
+    go ownDomain = do
+      mChan <- timeout 1_000_000 (readMVar env.channelMVar)
+      case mChan of
+        Nothing -> throwM NoRabbitMqChannel
+        Just chan -> do
+          liftIO $ enqueue chan env.requestId ownDomain remoteDomain deliveryMode action
+
+enqueueNotificationsConcurrently ::
+  (Foldable f, Functor f) =>
+  Env ->
+  Q.DeliveryMode ->
+  f (Remote x) ->
+  (Remote [x] -> FedQueueClient c a) ->
+  IO [Remote a]
+enqueueNotificationsConcurrently env m xs f =
+  enqueueNotificationsConcurrentlyBuckets env m (bucketRemote xs) f
+
+enqueueNotificationsConcurrentlyBuckets ::
+  (Foldable f) =>
+  Env ->
+  Q.DeliveryMode ->
+  f (Remote x) ->
+  (Remote x -> FedQueueClient c a) ->
+  IO [Remote a]
+enqueueNotificationsConcurrentlyBuckets env m xs f = do
+  case toList xs of
+    -- only attempt to get a channel if there is at least one notification to send
+    [] -> pure []
+    _ -> do
+      pooledForConcurrentlyN 8 (toList xs) $ \r ->
+        qualifyAs r
+          <$> enqueueSingleNotification env (tDomain r) m (f r)
+
+data NoRabbitMqChannel = NoRabbitMqChannel
+  deriving (Show)
+
+instance Exception NoRabbitMqChannel
diff --git a/libs/wire-subsystems/src/Wire/BackgroundJobsPublisher.hs b/libs/wire-subsystems/src/Wire/BackgroundJobsPublisher.hs
new file mode 100644
index 0000000000..9c65214dfc
--- /dev/null
+++ b/libs/wire-subsystems/src/Wire/BackgroundJobsPublisher.hs
@@ -0,0 +1,12 @@
+{-# LANGUAGE TemplateHaskell #-}
+
+module Wire.BackgroundJobsPublisher where
+
+import Data.Id
+import Polysemy
+import Wire.API.BackgroundJobs (JobPayload)
+
+data BackgroundJobsPublisher m a where
+  PublishJob :: JobId -> JobPayload -> BackgroundJobsPublisher m ()
+
+makeSem ''BackgroundJobsPublisher
diff --git a/libs/wire-subsystems/src/Wire/BackgroundJobsPublisher/Null.hs b/libs/wire-subsystems/src/Wire/BackgroundJobsPublisher/Null.hs
new file mode 100644
index 0000000000..87cc32e530
--- /dev/null
+++ b/libs/wire-subsystems/src/Wire/BackgroundJobsPublisher/Null.hs
@@ -0,0 +1,9 @@
+module Wire.BackgroundJobsPublisher.Null where
+
+import Imports
+import Polysemy
+import Wire.BackgroundJobsPublisher (BackgroundJobsPublisher (..))
+
+interpretBackgroundJobsPublisherNoConfig :: InterpreterFor BackgroundJobsPublisher r
+interpretBackgroundJobsPublisherNoConfig = interpret $ \case
+  PublishJob {} -> pure ()
diff --git a/libs/wire-subsystems/src/Wire/BackgroundJobsPublisher/RabbitMQ.hs b/libs/wire-subsystems/src/Wire/BackgroundJobsPublisher/RabbitMQ.hs
new file mode 100644
index 0000000000..4475bf03c0
--- /dev/null
+++ b/libs/wire-subsystems/src/Wire/BackgroundJobsPublisher/RabbitMQ.hs
@@ -0,0 +1,67 @@
+module Wire.BackgroundJobsPublisher.RabbitMQ where
+
+import Data.Aeson qualified as Aeson
+import Data.Id (JobId, RequestId (..), idToText)
+import Data.Text.Encoding qualified as T
+import Imports
+import Network.AMQP qualified as Q
+import Polysemy
+import Polysemy.Input
+import Wire.API.BackgroundJobs
+import Wire.BackgroundJobsPublisher (BackgroundJobsPublisher (..))
+import Wire.BackgroundJobsPublisher.Null (interpretBackgroundJobsPublisherNoConfig)
+
+interpretBackgroundJobsPublisherRabbitMQOptional ::
+  ( Member (Embed IO) r
+  ) =>
+  RequestId ->
+  Maybe (MVar Q.Channel) ->
+  InterpreterFor BackgroundJobsPublisher r
+interpretBackgroundJobsPublisherRabbitMQOptional requestId =
+  \case
+    Nothing -> interpretBackgroundJobsPublisherNoConfig
+    Just channelRef ->
+      runInputSem (readMVar channelRef)
+        . interpretBackgroundJobsPublisherRabbitMQ requestId
+        . raiseUnder
+
+interpretBackgroundJobsPublisherRabbitMQ ::
+  ( Member (Embed IO) r,
+    Member (Input Q.Channel) r
+  ) =>
+  RequestId ->
+  InterpreterFor BackgroundJobsPublisher r
+interpretBackgroundJobsPublisherRabbitMQ requestId =
+  interpret $ \case
+    PublishJob jobId jobPayload -> do
+      channel <- input
+      publishJob requestId channel jobId jobPayload
+
+publishJob ::
+  ( Member (Embed IO) r
+  ) =>
+  RequestId ->
+  Q.Channel ->
+  JobId ->
+  JobPayload ->
+  Sem r ()
+publishJob requestId channel jobId jobPayload = do
+  let job =
+        Job
+          { payload = jobPayload,
+            jobId = jobId,
+            requestId = requestId
+          }
+      msg =
+        Q.newMsg
+          { Q.msgBody = Aeson.encode job,
+            Q.msgContentType = Just "application/json",
+            Q.msgID = Just (idToText job.jobId),
+            Q.msgCorrelationID = Just $ T.decodeUtf8 job.requestId.unRequestId
+          }
+
+  liftIO $ do
+    ensureBackgroundJobsQueue channel
+    -- Passing "" for `exchangeName` publishes to the default exchange in RabbitMQ.
+    -- The default exchange routes directly to the queue whose name equals the `routingKey`.
+    void $ Q.publishMsg channel "" backgroundJobsRoutingKey msg
diff --git a/libs/wire-subsystems/src/Wire/BackgroundJobsRunner.hs b/libs/wire-subsystems/src/Wire/BackgroundJobsRunner.hs
new file mode 100644
index 0000000000..4515563ef1
--- /dev/null
+++ b/libs/wire-subsystems/src/Wire/BackgroundJobsRunner.hs
@@ -0,0 +1,11 @@
+{-# LANGUAGE TemplateHaskell #-}
+
+module Wire.BackgroundJobsRunner where
+
+import Polysemy
+import Wire.API.BackgroundJobs (Job)
+
+data BackgroundJobsRunner m a where
+  RunJob :: Job -> BackgroundJobsRunner m ()
+
+makeSem ''BackgroundJobsRunner
diff --git a/libs/wire-subsystems/src/Wire/BackgroundJobsRunner/Interpreter.hs b/libs/wire-subsystems/src/Wire/BackgroundJobsRunner/Interpreter.hs
new file mode 100644
index 0000000000..f521ffcaf4
--- /dev/null
+++ b/libs/wire-subsystems/src/Wire/BackgroundJobsRunner/Interpreter.hs
@@ -0,0 +1,143 @@
+{-# LANGUAGE RecordWildCards #-}
+
+module Wire.BackgroundJobsRunner.Interpreter where
+
+import Data.ByteString.Conversion (toByteString)
+import Data.Default
+import Data.Id
+import Data.List.NonEmpty (nonEmpty)
+import Data.Qualified
+import Data.Set qualified as Set
+import Data.Singletons
+import Data.Vector qualified as V
+import Imports
+import Polysemy
+import Polysemy.Input
+import Polysemy.TinyLog (TinyLog)
+import Polysemy.TinyLog qualified as Log
+import System.Logger.Message (field, msg, val)
+import Wire.API.BackgroundJobs
+import Wire.API.Conversation (ConversationJoin (..), JoinType (ExternalAdd))
+import Wire.API.Conversation.Action.Tag
+import Wire.API.Conversation.Role (roleNameWireMember)
+import Wire.API.UserGroup
+import Wire.BackgroundJobsPublisher
+import Wire.BackgroundJobsRunner (BackgroundJobsRunner (..))
+import Wire.ConversationStore (ConversationStore, getConversation, upsertMembers)
+import Wire.ConversationSubsystem
+import Wire.Sem.Random
+import Wire.StoredConversation
+import Wire.UserGroupStore (UserGroupStore, getUserGroup, getUserGroupChannels)
+import Wire.UserList (toUserList)
+
+interpretBackgroundJobsRunner ::
+  ( Member UserGroupStore r,
+    Member BackgroundJobsPublisher r,
+    Member (Input (Local ())) r,
+    Member ConversationStore r,
+    Member ConversationSubsystem r,
+    Member Random r,
+    Member TinyLog r
+  ) =>
+  InterpreterFor BackgroundJobsRunner r
+interpretBackgroundJobsRunner = interpret $ \case
+  RunJob job -> runJob job
+
+runJob ::
+  ( Member UserGroupStore r,
+    Member BackgroundJobsPublisher r,
+    Member (Input (Local ())) r,
+    Member ConversationStore r,
+    Member ConversationSubsystem r,
+    Member Random r,
+    Member TinyLog r
+  ) =>
+  Job ->
+  Sem r ()
+runJob job = case job.payload of
+  JobSyncUserGroupAndChannel payload -> runSyncUserGroupAndChannel job.jobId job.requestId payload
+  JobSyncUserGroup payload -> runSyncUserGroup job.jobId job.requestId payload
+
+runSyncUserGroupAndChannel ::
+  ( Member UserGroupStore r,
+    Member (Input (Local ())) r,
+    Member ConversationStore r,
+    Member ConversationSubsystem r,
+    Member TinyLog r
+  ) =>
+  JobId ->
+  RequestId ->
+  SyncUserGroupAndChannel ->
+  Sem r ()
+runSyncUserGroupAndChannel _ _ (SyncUserGroupAndChannel {..}) = do
+  loc <- input
+  mUserGroup <- getUserGroup teamId userGroupId False
+  when (isNothing mUserGroup) $
+    Log.warn $
+      field "team" (toByteString teamId)
+        . field "user_group" (toByteString userGroupId)
+        . field "conv" (toByteString convId)
+        . msg (val "User group not found for sync")
+  mConv <- getConversation convId
+  when (isNothing mConv) $
+    Log.warn $
+      field "conv" (toByteString convId)
+        . field "team" (toByteString teamId)
+        . field "user_group" (toByteString userGroupId)
+        . msg (val "Conversation not found for sync")
+  for_ mConv $ \conv -> do
+    let usersFromGroup = foldMap (runIdentity . (.members)) mUserGroup
+        (botMembers, localMembers) = localBotsAndUsers conv.localMembers
+        usersNotInConv = V.filter (\u -> u `notElem` fmap (.id_) localMembers) usersFromGroup
+
+    for_ (nonEmpty . V.toList $ usersNotInConv) $ \usersUnqualified -> do
+      let role = roleNameWireMember
+          users = fmap (flip Qualified (tDomain loc)) usersUnqualified
+          userList = toUserList loc users
+          action = ConversationJoin {joinType = ExternalAdd, ..}
+
+      -- TODO: how are we going to deal with conversation member limit, which affects the fan out of notifications here?
+      (extraLocals, extraRemotes) <- upsertMembers convId (fmap (,role) userList)
+      void $
+        notifyConversationAction
+          (sing @'ConversationJoinTag)
+          (Qualified actor (tDomain loc))
+          False
+          Nothing
+          (loc $> conv)
+          (Set.fromList $ fmap (.id_) (localMembers <> extraLocals))
+          (Set.fromList $ fmap (.id_) (conv.remoteMembers <> extraRemotes))
+          (Set.fromList botMembers)
+          action
+          def
+
+localBotsAndUsers :: (Foldable f) => f LocalMember -> ([BotMember], [LocalMember])
+localBotsAndUsers = foldMap botOrUser
+  where
+    botOrUser m = case m.service of
+      -- we drop invalid bots here, which shouldn't happen
+      Just _ -> (toList (newBotMember m), [])
+      Nothing -> ([], [m])
+
+runSyncUserGroup ::
+  ( Member UserGroupStore r,
+    Member BackgroundJobsPublisher r,
+    Member Random r,
+    Member TinyLog r
+  ) =>
+  JobId ->
+  RequestId ->
+  SyncUserGroup ->
+  Sem r ()
+runSyncUserGroup _ _ SyncUserGroup {..} = do
+  mChannels <- getUserGroupChannels teamId userGroupId
+  when (isNothing mChannels) $
+    Log.warn $
+      field "team" (toByteString teamId)
+        . field "user_group" (toByteString userGroupId)
+        . msg (val "No channels found for user group")
+  let channels = fromMaybe mempty mChannels
+  for_ channels $ \convId -> do
+    let syncUserGroupAndChannel = SyncUserGroupAndChannel {..}
+    jobId <- newId
+    publishJob jobId (JobSyncUserGroupAndChannel syncUserGroupAndChannel)
diff --git a/libs/wire-subsystems/src/Wire/ConversationStore.hs b/libs/wire-subsystems/src/Wire/ConversationStore.hs
index 0bd1191278..65ca5e1e7c 100644
--- a/libs/wire-subsystems/src/Wire/ConversationStore.hs
+++ b/libs/wire-subsystems/src/Wire/ConversationStore.hs
@@ -19,10 +19,12 @@
 
 module Wire.ConversationStore where
 
+import Data.Aeson
 import Data.Id
 import Data.Misc
 import Data.Qualified
 import Data.Range
+import Data.Text qualified as Text
 import Data.Time.Clock
 import Imports
 import Polysemy
@@ -143,3 +145,21 @@ acceptConnectConversation cid = setConversationType cid One2OneConv
 -- | Add a member to a local conversation, as an admin.
 upsertMember :: (Member ConversationStore r) => Local ConvId -> Local UserId -> Sem r [LocalMember]
 upsertMember c u = fst <$> upsertMembers (tUnqualified c) (UserList [(tUnqualified u, roleNameWireAdmin)] [])
+
+data StorageLocation = CassandraStorage | PostgresqlStorage
+  deriving (Show, Eq)
+
+instance FromJSON StorageLocation where
+  parseJSON = withText "StorageLocation" $ \case
+    "cassandra" -> pure CassandraStorage
+    "postgresql" -> pure PostgresqlStorage
+    x -> fail $ "Invalid storage location: " <> Text.unpack x <> ". Valid options: cassandra, postgresql"
+
+data PostgresMigrationOpts = PostgresMigrationOpts
+  { conversation :: StorageLocation
+  }
+  deriving (Show, Eq)
+
+instance FromJSON PostgresMigrationOpts where
+  parseJSON = withObject "PostgresMigrationOpts" $ \o ->
+    PostgresMigrationOpts <$> o .: "conversation"
diff --git a/libs/wire-subsystems/src/Wire/ConversationSubsystem.hs b/libs/wire-subsystems/src/Wire/ConversationSubsystem.hs
new file mode 100644
index 0000000000..cc7995ea0d
--- /dev/null
+++ b/libs/wire-subsystems/src/Wire/ConversationSubsystem.hs
@@ -0,0 +1,29 @@
+{-# LANGUAGE TemplateHaskell #-}
+
+module Wire.ConversationSubsystem where
+
+import Data.Id
+import Data.Qualified
+import Data.Singletons (Sing)
+import Imports
+import Polysemy
+import Wire.API.Conversation (ExtraConversationData)
+import Wire.API.Conversation.Action
+import Wire.NotificationSubsystem (LocalConversationUpdate)
+import Wire.StoredConversation
+
+data ConversationSubsystem m a where
+  NotifyConversationAction ::
+    Sing tag ->
+    Qualified UserId ->
+    Bool ->
+    Maybe ConnId ->
+    Local StoredConversation ->
+    Set UserId ->
+    Set (Remote UserId) ->
+    Set BotMember ->
+    ConversationAction (tag :: ConversationActionTag) ->
+    ExtraConversationData ->
+    ConversationSubsystem r LocalConversationUpdate
+
+makeSem ''ConversationSubsystem
diff --git a/libs/wire-subsystems/src/Wire/ConversationSubsystem/Interpreter.hs b/libs/wire-subsystems/src/Wire/ConversationSubsystem/Interpreter.hs
new file mode 100644
index 0000000000..b46a27f650
--- /dev/null
+++ b/libs/wire-subsystems/src/Wire/ConversationSubsystem/Interpreter.hs
@@ -0,0 +1,116 @@
+module Wire.ConversationSubsystem.Interpreter where
+
+import Data.Default
+import Data.Id
+import Data.Json.Util (ToJSONObject (toJSONObject))
+import Data.Qualified
+import Data.Singletons (Sing)
+import Imports
+import Network.AMQP qualified as Q
+import Polysemy
+import Polysemy.Error
+import Wire.API.Conversation hiding (Member)
+import Wire.API.Conversation.Action
+import Wire.API.Conversation.CellsState (CellsState (..))
+import Wire.API.Event.Conversation
+import Wire.API.Federation.API (makeConversationUpdateBundle, sendBundle)
+import Wire.API.Federation.API.Galley.Notifications (ConversationUpdate (..))
+import Wire.API.Federation.Error (FederationError)
+import Wire.API.Push.V2 qualified as PushV2
+import Wire.BackendNotificationQueueAccess (BackendNotificationQueueAccess, enqueueNotificationsConcurrently)
+import Wire.ConversationSubsystem
+import Wire.ExternalAccess (ExternalAccess, deliverAsync)
+import Wire.NotificationSubsystem as NS
+import Wire.Sem.Now (Now)
+import Wire.Sem.Now qualified as Now
+import Wire.StoredConversation
+
+interpretConversationSubsystem ::
+  ( Member (Error FederationError) r,
+    Member BackendNotificationQueueAccess r,
+    Member NotificationSubsystem r,
+    Member ExternalAccess r,
+    Member Now r
+  ) =>
+  Sem (ConversationSubsystem : r) a ->
+  Sem r a
+interpretConversationSubsystem = interpret $ \case
+  NotifyConversationAction tag quid notifyOrigDomain con lconv targetsLocal targetsRemote targetsBots action extraData ->
+    notifyConversationActionImpl tag quid notifyOrigDomain con lconv targetsLocal targetsRemote targetsBots action extraData
+
+notifyConversationActionImpl ::
+  forall tag r.
+  ( Member BackendNotificationQueueAccess r,
+    Member ExternalAccess r,
+    Member (Error FederationError) r,
+    Member Now r,
+    Member NotificationSubsystem r
+  ) =>
+  Sing tag ->
+  Qualified UserId ->
+  Bool ->
+  Maybe ConnId ->
+  Local StoredConversation ->
+  Set UserId ->
+  Set (Remote UserId) ->
+  Set BotMember ->
+  ConversationAction (tag :: ConversationActionTag) ->
+  ExtraConversationData ->
+  Sem r LocalConversationUpdate
+notifyConversationActionImpl tag quid notifyOrigDomain con lconv targetsLocal targetsRemote targetsBots action extraData = do
+  now <- Now.get
+  let lcnv = fmap (.id_) lconv
+      conv = tUnqualified lconv
+      tid = conv.metadata.cnvmTeam
+      e = conversationActionToEvent tag now quid (tUntagged lcnv) extraData Nothing tid action
+      mkUpdate uids =
+        ConversationUpdate
+          { time = now,
+            origUserId = quid,
+            convId = tUnqualified lcnv,
+            alreadyPresentUsers = uids,
+            action = SomeConversationAction tag action,
+            extraConversationData = Just extraData
+          }
+  update <-
+    fmap (fromMaybe (mkUpdate []) . asum . map tUnqualified) $
+      enqueueNotificationsConcurrently Q.Persistent (toList targetsRemote) $
+        \ruids -> do
+          let update = mkUpdate (tUnqualified ruids)
+          if notifyOrigDomain || tDomain ruids /= qDomain quid
+            then do
+              makeConversationUpdateBundle update >>= sendBundle
+              pure Nothing
+            else pure (Just update)
+
+  pushConversationEvent con conv.metadata.cnvmCellsState e (qualifyAs lcnv targetsLocal) targetsBots
+
+  pure $ LocalConversationUpdate {lcuEvent = e, lcuUpdate = update}
+
+pushConversationEvent ::
+  ( Member ExternalAccess r,
+    Member NotificationSubsystem r,
+    Foldable f
+  ) =>
+  Maybe ConnId ->
+  CellsState ->
+  Event ->
+  Local (f UserId) ->
+  f BotMember ->
+  Sem r ()
+pushConversationEvent conn st e lusers bots = do
+  pushNotifications [(newConversationEventPush (fmap toList lusers)) {conn}]
+  deliverAsync (map (,e) (toList bots))
+  where
+    newConversationEventPush :: Local [UserId] -> Push
+    newConversationEventPush users =
+      let musr = guard (tDomain users == qDomain e.evtFrom) $> qUnqualified e.evtFrom
+       in def
+            { origin = musr,
+              json = toJSONObject e,
+              recipients = map userRecipient (tUnqualified users),
+              isCellsEvent = shouldPushToCells st e
+            }
+
+    userRecipient :: UserId -> Recipient
+    userRecipient u = Recipient {recipientUserId = u, recipientClients = PushV2.RecipientClientsAll}
diff --git a/services/galley/src/Galley/Effects/ExternalAccess.hs b/libs/wire-subsystems/src/Wire/ExternalAccess.hs
similarity index 93%
rename from services/galley/src/Galley/Effects/ExternalAccess.hs
rename to libs/wire-subsystems/src/Wire/ExternalAccess.hs
index d54509d304..81d25fad4e 100644
--- a/services/galley/src/Galley/Effects/ExternalAccess.hs
+++ b/libs/wire-subsystems/src/Wire/ExternalAccess.hs
@@ -2,7 +2,7 @@
 
 -- This file is part of the Wire Server implementation.
 --
--- Copyright (C) 2022 Wire Swiss GmbH <opensource@wire.com>
+-- Copyright (C) 2025 Wire Swiss GmbH <opensource@wire.com>
 --
 -- This program is free software: you can redistribute it and/or modify it under
 -- the terms of the GNU Affero General Public License as published by the Free
@@ -17,7 +17,7 @@
 -- You should have received a copy of the GNU Affero General Public License along
 -- with this program. If not, see <https://www.gnu.org/licenses/>.
 
-module Galley.Effects.ExternalAccess
+module Wire.ExternalAccess
   ( -- * External access effect
     ExternalAccess (..),
     deliver,
diff --git a/services/galley/src/Galley/External.hs b/libs/wire-subsystems/src/Wire/ExternalAccess/External.hs
similarity index 61%
rename from services/galley/src/Galley/External.hs
rename to libs/wire-subsystems/src/Wire/ExternalAccess/External.hs
index f4c0b04267..11b8a27874 100644
--- a/services/galley/src/Galley/External.hs
+++ b/libs/wire-subsystems/src/Wire/ExternalAccess/External.hs
@@ -1,6 +1,6 @@
 -- This file is part of the Wire Server implementation.
 --
--- Copyright (C) 2022 Wire Swiss GmbH <opensource@wire.com>
+-- Copyright (C) 2025 Wire Swiss GmbH <opensource@wire.com>
 --
 -- This program is free software: you can redistribute it and/or modify it under
 -- the terms of the GNU Affero General Public License as published by the Free
@@ -15,123 +15,162 @@
 -- You should have received a copy of the GNU Affero General Public License along
 -- with this program. If not, see <https://www.gnu.org/licenses/>.
 
-module Galley.External (interpretExternalAccess) where
+module Wire.ExternalAccess.External (interpretExternalAccess, ExtEnv (..)) where
 
 import Bilge.Request
 import Bilge.Retry (httpHandlers)
+import Control.Concurrent.Async (Async)
+import Control.Exception (try)
 import Control.Lens
 import Control.Retry
 import Data.ByteString.Conversion.To
 import Data.Id
 import Data.Misc
-import Galley.Cassandra.Services
-import Galley.Cassandra.Util
-import Galley.Effects
-import Galley.Effects.ExternalAccess (ExternalAccess (..))
-import Galley.Effects.FireAndForget
-import Galley.Env
-import Galley.Monad
 import Imports
 import Network.HTTP.Client qualified as Http
 import Network.HTTP.Types.Method
 import Network.HTTP.Types.Status (status410)
+import OpenSSL.Session qualified as Ssl
 import Polysemy
-import Polysemy.Input
+import Polysemy.Async qualified as Async
 import Polysemy.TinyLog
 import Ssl.Util (withVerifiedSslConnection)
-import System.Logger.Class qualified as Log
 import System.Logger.Message (field, msg, val, (~~))
 import URI.ByteString
-import UnliftIO (Async, async, waitCatch)
 import Wire.API.Bot.Service
 import Wire.API.Event.Conversation (Event)
 import Wire.API.Provider.Service (serviceRefId, serviceRefProvider)
 import Wire.BrigAPIAccess
+import Wire.ExternalAccess (ExternalAccess (..))
+import Wire.FireAndForget
+import Wire.ServiceStore
 import Wire.StoredConversation (BotMember, botMemId, botMemService)
+import Wire.Util
+
+data ExtEnv = ExtEnv
+  { extGetManager :: (Http.Manager, [Fingerprint Rsa] -> Ssl.SSL -> IO ())
+  }
 
 interpretExternalAccess ::
-  ( Member (Embed IO) r,
-    Member (Input Env) r,
-    Member TinyLog r,
+  ( Member TinyLog r,
     Member BrigAPIAccess r,
-    Member FireAndForget r
+    Member FireAndForget r,
+    Member ServiceStore r,
+    Member (Final IO) r,
+    Member Async.Async r
   ) =>
+  ExtEnv ->
   Sem (ExternalAccess ': r) a ->
   Sem r a
-interpretExternalAccess = interpret $ \case
+interpretExternalAccess env = interpret $ \case
   Deliver pp -> do
     logEffect "ExternalAccess.Deliver"
-    embedApp $ deliver (toList pp)
+    deliver env (toList pp)
   DeliverAsync pp -> do
     logEffect "ExternalAccess.DeliverAsync"
-    embedApp $ deliverAsync (toList pp)
+    deliverAsync env (toList pp)
   DeliverAndDeleteAsync cid pp -> do
     logEffect "ExternalAccess.DeliverAndDeleteAsync"
-    deliverAndDeleteAsync cid (toList pp)
+    deliverAndDeleteAsync env cid (toList pp)
 
 -- | Like deliver, but ignore orphaned bots and return immediately.
 --
 -- FUTUREWORK: Check if this can be removed.
-deliverAsync :: [(BotMember, Event)] -> App ()
-deliverAsync = void . forkIO . void . deliver
+deliverAsync ::
+  ( Member FireAndForget r,
+    Member TinyLog r,
+    Member ServiceStore r,
+    Member (Final IO) r,
+    Member Async.Async r
+  ) =>
+  ExtEnv ->
+  [(BotMember, Event)] ->
+  Sem r ()
+deliverAsync env = fireAndForget . void . deliver env
 
 -- | Like deliver, but remove orphaned bots and return immediately.
-deliverAndDeleteAsync :: (Member (Input Env) r, Member (Embed IO) r, Member BrigAPIAccess r, Member FireAndForget r) => ConvId -> [(BotMember, Event)] -> Sem r ()
-deliverAndDeleteAsync cnv pushes = fireAndForget $ do
-  gone <- embedApp $ deliver pushes
+deliverAndDeleteAsync ::
+  ( Member BrigAPIAccess r,
+    Member FireAndForget r,
+    Member TinyLog r,
+    Member ServiceStore r,
+    Member (Final IO) r,
+    Member Async.Async r
+  ) =>
+  ExtEnv ->
+  ConvId ->
+  [(BotMember, Event)] ->
+  Sem r ()
+deliverAndDeleteAsync env cnv pushes = fireAndForget $ do
+  gone <- deliver env pushes
   mapM_ (deleteBot cnv . botMemId) gone
 
-deliver :: [(BotMember, Event)] -> App [BotMember]
-deliver pp = mapM (async . exec) pp >>= foldM eval [] . zip (map fst pp)
+deliver ::
+  forall r.
+  ( Member ServiceStore r,
+    Member TinyLog r,
+    Member Async.Async r,
+    Member (Final IO) r
+  ) =>
+  ExtEnv ->
+  [(BotMember, Event)] ->
+  Sem r [BotMember]
+deliver env pp = mapM (Async.async . exec) pp >>= foldM eval [] . zip (map fst pp)
   where
-    exec :: (BotMember, Event) -> App Bool
+    exec :: (BotMember, Event) -> Sem r (Either SomeException Bool)
     exec (b, e) =
-      lookupService (botMemService b) >>= \case
-        Nothing -> pure False
-        Just s -> do
-          deliver1 s b e
-          pure True
-    eval :: [BotMember] -> (BotMember, Async Bool) -> App [BotMember]
+      getService (botMemService b) >>= \case
+        Nothing -> pure $ Right False
+        Just s ->
+          embedFinal $ try $ (deliver1 env s b e $> True)
+    eval :: [BotMember] -> (BotMember, Async (Maybe (Either SomeException Bool))) -> Sem r [BotMember]
     eval gone (b, a) = do
       let s = botMemService b
-      r <- waitCatch a
+      r <- Async.await a
       case r of
-        Right True -> do
-          Log.debug $
+        Just (Right True) -> do
+          debug $
             field "provider" (toByteString (s ^. serviceRefProvider))
               ~~ field "service" (toByteString (s ^. serviceRefId))
               ~~ field "bot" (toByteString (botMemId b))
               ~~ msg (val "External delivery success")
           pure gone
-        Right False -> do
-          Log.debug $
+        Just (Right False) -> do
+          debug $
             field "provider" (toByteString (s ^. serviceRefProvider))
               ~~ field "service" (toByteString (s ^. serviceRefId))
               ~~ field "bot" (toByteString (botMemId b))
               ~~ msg (val "External service gone")
           pure (b : gone)
-        Left ex
+        Just (Left ex)
           | Just (Http.HttpExceptionRequest _ (Http.StatusCodeException rs _)) <- fromException ex,
             Http.responseStatus rs == status410 -> do
-              Log.debug $
+              debug $
                 field "provider" (toByteString (s ^. serviceRefProvider))
                   ~~ field "service" (toByteString (s ^. serviceRefId))
                   ~~ field "bot" (toByteString (botMemId b))
                   ~~ msg (val "External bot gone")
               pure (b : gone)
-        Left ex -> do
-          Log.info $
+        Just (Left ex) -> do
+          info $
             field "provider" (toByteString (s ^. serviceRefProvider))
               ~~ field "service" (toByteString (s ^. serviceRefId))
               ~~ field "bot" (toByteString (botMemId b))
               ~~ field "error" (show ex)
               ~~ msg (val "External delivery failure")
           pure gone
+        Nothing -> do
+          info $
+            field "provider" (toByteString (s ^. serviceRefProvider))
+              ~~ field "service" (toByteString (s ^. serviceRefId))
+              ~~ field "bot" (toByteString (botMemId b))
+              ~~ msg (val "External delivery failure due to local error in Async")
+          pure gone
 
 -- Internal -------------------------------------------------------------------
 
-deliver1 :: Service -> BotMember -> Event -> App ()
-deliver1 s bm e
+deliver1 :: ExtEnv -> Service -> BotMember -> Event -> IO ()
+deliver1 env s bm e
   | s ^. serviceEnabled = do
       let t = toByteString' (s ^. serviceToken)
       let u = s ^. serviceUrl
@@ -139,7 +178,7 @@ deliver1 s bm e
       let HttpsUrl url = u
       recovering x3 httpHandlers $
         const $
-          sendMessage (s ^. serviceFingerprints) $
+          sendMessage env (s ^. serviceFingerprints) $
             method POST
               . maybe id host (urlHost u)
               . maybe (port 443) port (urlPort u)
@@ -160,9 +199,9 @@ urlPort (HttpsUrl u) = do
   p <- a ^. authorityPortL
   pure (fromIntegral (p ^. portNumberL))
 
-sendMessage :: [Fingerprint Rsa] -> (Request -> Request) -> App ()
-sendMessage fprs reqBuilder = do
-  (man, verifyFingerprints) <- view (extEnv . extGetManager)
+sendMessage :: ExtEnv -> [Fingerprint Rsa] -> (Request -> Request) -> IO ()
+sendMessage env fprs reqBuilder = do
+  let (man, verifyFingerprints) = env.extGetManager
   liftIO . withVerifiedSslConnection (verifyFingerprints fprs) man reqBuilder $ \req ->
     Http.withResponse req man (const $ pure ())
 
diff --git a/services/galley/src/Galley/Effects/FireAndForget.hs b/libs/wire-subsystems/src/Wire/FireAndForget.hs
similarity index 94%
rename from services/galley/src/Galley/Effects/FireAndForget.hs
rename to libs/wire-subsystems/src/Wire/FireAndForget.hs
index b78264acaf..bcc2ebdfa0 100644
--- a/services/galley/src/Galley/Effects/FireAndForget.hs
+++ b/libs/wire-subsystems/src/Wire/FireAndForget.hs
@@ -2,7 +2,7 @@
 
 -- This file is part of the Wire Server implementation.
 --
--- Copyright (C) 2022 Wire Swiss GmbH <opensource@wire.com>
+-- Copyright (C) 2025 Wire Swiss GmbH <opensource@wire.com>
 --
 -- This program is free software: you can redistribute it and/or modify it under
 -- the terms of the GNU Affero General Public License as published by the Free
@@ -17,7 +17,7 @@
 -- You should have received a copy of the GNU Affero General Public License along
 -- with this program. If not, see <https://www.gnu.org/licenses/>.
 
-module Galley.Effects.FireAndForget
+module Wire.FireAndForget
   ( FireAndForget,
     fireAndForget,
     spawnMany,
diff --git a/libs/wire-subsystems/src/Wire/NotificationSubsystem.hs b/libs/wire-subsystems/src/Wire/NotificationSubsystem.hs
index c2d7d8118c..735dd5c300 100644
--- a/libs/wire-subsystems/src/Wire/NotificationSubsystem.hs
+++ b/libs/wire-subsystems/src/Wire/NotificationSubsystem.hs
@@ -8,6 +8,8 @@ import Data.Default
 import Data.Id
 import Imports
 import Polysemy
+import Wire.API.Event.Conversation
+import Wire.API.Federation.API.Galley.Notifications (ConversationUpdate)
 import Wire.API.Push.V2 hiding (Push (..), Recipient, newPush)
 import Wire.Arbitrary
 
@@ -32,6 +34,12 @@ data Push = Push
   deriving stock (Eq, Generic, Show)
   deriving (Arbitrary) via GenericUniform Push
 
+data LocalConversationUpdate = LocalConversationUpdate
+  { lcuEvent :: Event,
+    lcuUpdate :: ConversationUpdate
+  }
+  deriving (Show)
+
 -- | This subsystem governs mechanisms to send notifications to users.
 data NotificationSubsystem m a where
   -- | Bulk push notifications
diff --git a/libs/wire-subsystems/src/Wire/NotificationSubsystem/Interpreter.hs b/libs/wire-subsystems/src/Wire/NotificationSubsystem/Interpreter.hs
index e3dbcec587..63d1a05969 100644
--- a/libs/wire-subsystems/src/Wire/NotificationSubsystem/Interpreter.hs
+++ b/libs/wire-subsystems/src/Wire/NotificationSubsystem/Interpreter.hs
@@ -1,9 +1,9 @@
 module Wire.NotificationSubsystem.Interpreter where
 
-import Bilge (RequestId)
 import Control.Concurrent.Async (Async)
 import Control.Lens (set, (.~))
 import Data.Aeson
+import Data.Id
 import Data.List1 (List1)
 import Data.List1 qualified as List1
 import Data.Proxy
@@ -21,10 +21,10 @@ import Polysemy.TinyLog qualified as P
 import System.Logger.Class as Log
 import Wire.API.Push.V2 hiding (Push (..), Recipient, newPush)
 import Wire.API.Push.V2 qualified as V2
-import Wire.API.Team.Member
+import Wire.API.Team.HardTruncationLimit (HardTruncationLimit)
 import Wire.GundeckAPIAccess (GundeckAPIAccess)
 import Wire.GundeckAPIAccess qualified as GundeckAPIAccess
-import Wire.NotificationSubsystem
+import Wire.NotificationSubsystem as NS
 import Wire.Sem.Delay
 
 -- | We interpret this using 'GundeckAPIAccess' so we can mock it out for testing.
@@ -155,7 +155,7 @@ chunkPushes maxRecipients
     splitPush :: Natural -> Push -> (Push, Push)
     splitPush n p =
       let (r1, r2) = splitAt (fromIntegral n) (toList p.recipients)
-       in (p {recipients = r1}, p {recipients = r2})
+       in (p {NS.recipients = r1}, p {NS.recipients = r2})
 
 pushSlowlyImpl ::
   ( Member Delay r,
diff --git a/services/galley/src/Galley/Effects/ServiceStore.hs b/libs/wire-subsystems/src/Wire/ServiceStore.hs
similarity index 97%
rename from services/galley/src/Galley/Effects/ServiceStore.hs
rename to libs/wire-subsystems/src/Wire/ServiceStore.hs
index 18949b7a47..80d9cc5bdb 100644
--- a/services/galley/src/Galley/Effects/ServiceStore.hs
+++ b/libs/wire-subsystems/src/Wire/ServiceStore.hs
@@ -17,7 +17,7 @@
 -- You should have received a copy of the GNU Affero General Public License along
 -- with this program. If not, see <https://www.gnu.org/licenses/>.
 
-module Galley.Effects.ServiceStore
+module Wire.ServiceStore
   ( -- * Service effect
     ServiceStore (..),
 
diff --git a/services/galley/src/Galley/Cassandra/Services.hs b/libs/wire-subsystems/src/Wire/ServiceStore/Cassandra.hs
similarity index 52%
rename from services/galley/src/Galley/Cassandra/Services.hs
rename to libs/wire-subsystems/src/Wire/ServiceStore/Cassandra.hs
index 45ab448883..780df8f804 100644
--- a/services/galley/src/Galley/Cassandra/Services.hs
+++ b/libs/wire-subsystems/src/Wire/ServiceStore/Cassandra.hs
@@ -1,54 +1,36 @@
--- This file is part of the Wire Server implementation.
---
--- Copyright (C) 2022 Wire Swiss GmbH <opensource@wire.com>
---
--- This program is free software: you can redistribute it and/or modify it under
--- the terms of the GNU Affero General Public License as published by the Free
--- Software Foundation, either version 3 of the License, or (at your option) any
--- later version.
---
--- This program is distributed in the hope that it will be useful, but WITHOUT
--- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
--- FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
--- details.
---
--- You should have received a copy of the GNU Affero General Public License along
--- with this program. If not, see <https://www.gnu.org/licenses/>.
-
-module Galley.Cassandra.Services where
+module Wire.ServiceStore.Cassandra where
 
 import Cassandra
+import Cassandra qualified as C
 import Control.Lens
-import Galley.Cassandra.Queries
-import Galley.Cassandra.Store
-import Galley.Cassandra.Util
-import Galley.Effects.ServiceStore hiding (deleteService)
+import Data.Id
+import Data.Misc
 import Imports
 import Polysemy
-import Polysemy.Input
 import Polysemy.TinyLog
 import Wire.API.Bot.Service qualified as Bot
+import Wire.API.Provider
 import Wire.API.Provider.Service hiding (DeleteService)
-
--- Service --------------------------------------------------------------------
+import Wire.ServiceStore (ServiceStore (..))
+import Wire.Util
 
 interpretServiceStoreToCassandra ::
   ( Member (Embed IO) r,
-    Member (Input ClientState) r,
     Member TinyLog r
   ) =>
+  ClientState ->
   Sem (ServiceStore ': r) a ->
   Sem r a
-interpretServiceStoreToCassandra = interpret $ \case
+interpretServiceStoreToCassandra cassClient = interpret $ \case
   CreateService s -> do
     logEffect "ServiceStore.CreateService"
-    embedClient $ insertService s
+    embedClient cassClient $ insertService s
   GetService sr -> do
     logEffect "ServiceStore.GetService"
-    embedClient $ lookupService sr
+    embedClient cassClient $ lookupService sr
   DeleteService sr -> do
     logEffect "ServiceStore.DeleteService"
-    embedClient $ deleteService sr
+    embedClient cassClient $ deleteService sr
 
 insertService :: (MonadClient m) => Bot.Service -> m ()
 insertService s = do
@@ -70,3 +52,12 @@ lookupService s =
 
 deleteService :: (MonadClient m) => ServiceRef -> m ()
 deleteService s = retry x5 (write rmSrv (params LocalQuorum (s ^. serviceRefProvider, s ^. serviceRefId)))
+
+rmSrv :: PrepQuery W (ProviderId, ServiceId) ()
+rmSrv = "delete from service where provider = ? AND id = ?"
+
+insertSrv :: PrepQuery W (ProviderId, ServiceId, HttpsUrl, ServiceToken, C.Set (Fingerprint Rsa), Bool) ()
+insertSrv = "insert into service (provider, id, base_url, auth_token, fingerprints, enabled) values (?, ?, ?, ?, ?, ?)"
+
+selectSrv :: PrepQuery R (ProviderId, ServiceId) (HttpsUrl, ServiceToken, C.Set (Fingerprint Rsa), Bool)
+selectSrv = "select base_url, auth_token, fingerprints, enabled from service where provider = ? AND id = ?"
diff --git a/libs/wire-subsystems/src/Wire/StoredConversation.hs b/libs/wire-subsystems/src/Wire/StoredConversation.hs
index 71a5f7b024..d69dc4757e 100644
--- a/libs/wire-subsystems/src/Wire/StoredConversation.hs
+++ b/libs/wire-subsystems/src/Wire/StoredConversation.hs
@@ -35,6 +35,9 @@ data StoredConversation = StoredConversation
   }
   deriving (Show)
 
+instance HasCellsState StoredConversation where
+  getCellsState = getCellsState . (.metadata)
+
 type ConvRowWithId =
   ( ConvId,
     ConvType,
diff --git a/libs/wire-subsystems/src/Wire/UserGroupStore.hs b/libs/wire-subsystems/src/Wire/UserGroupStore.hs
index 98a1fd7d8f..ea49cd2943 100644
--- a/libs/wire-subsystems/src/Wire/UserGroupStore.hs
+++ b/libs/wire-subsystems/src/Wire/UserGroupStore.hs
@@ -44,5 +44,6 @@ data UserGroupStore m a where
   AddUserGroupChannels :: UserGroupId -> Vector ConvId -> UserGroupStore m ()
   UpdateUserGroupChannels :: UserGroupId -> Vector ConvId -> UserGroupStore m ()
   GetUserGroupIdsForUsers :: [UserId] -> UserGroupStore m (Map UserId [UserGroupId])
+  GetUserGroupChannels :: TeamId -> UserGroupId -> UserGroupStore m (Maybe (Vector ConvId))
 
 makeSem ''UserGroupStore
diff --git a/libs/wire-subsystems/src/Wire/UserGroupStore/Postgres.hs b/libs/wire-subsystems/src/Wire/UserGroupStore/Postgres.hs
index 2deb4b5db7..53c74e0c36 100644
--- a/libs/wire-subsystems/src/Wire/UserGroupStore/Postgres.hs
+++ b/libs/wire-subsystems/src/Wire/UserGroupStore/Postgres.hs
@@ -56,6 +56,7 @@ interpretUserGroupStoreToPostgres =
     AddUserGroupChannels gid convIds -> updateUserGroupChannels True gid convIds
     UpdateUserGroupChannels gid convIds -> updateUserGroupChannels False gid convIds
     GetUserGroupIdsForUsers uids -> getUserGroupIdsForUsers uids
+    GetUserGroupChannels tid gid -> getUserGroupChannels tid gid
 
 getUserGroupIdsForUsers :: (UserGroupStorePostgresEffectConstraints r) => [UserId] -> Sem r (Map UserId [UserGroupId])
 getUserGroupIdsForUsers uidsList = do
@@ -433,6 +434,35 @@ updateUserGroupChannels appendOnly gid convIds = do
           on conflict (user_group_id, conv_id) do nothing
           |]
 
+getUserGroupChannels ::
+  forall r.
+  (UserGroupStorePostgresEffectConstraints r) =>
+  TeamId ->
+  UserGroupId ->
+  Sem r (Maybe (Vector ConvId))
+getUserGroupChannels tid gid = do
+  pool <- input
+  result <- liftIO $ use pool session
+  either throw pure result
+  where
+    session :: Session (Maybe (Vector ConvId))
+    session = do
+      mbUuids <- statement (gid, tid) getChannelsStatement
+      pure (fmap (fmap Id) mbUuids)
+
+    getChannelsStatement :: Statement (UserGroupId, TeamId) (Maybe (Vector UUID))
+    getChannelsStatement =
+      lmap (\(g, t) -> (g.toUUID, t.toUUID)) $
+        [maybeStatement|
+          select
+            coalesce(
+              (select array_agg(ugc.conv_id) from user_group_channel ugc where ugc.user_group_id = ug.id),
+              array[]::uuid[]
+            ) :: uuid[]
+          from user_group ug
+          where ug.id = ($1 :: uuid) and ug.team_id = ($2 :: uuid)
+        |]
+
 crudUser ::
   forall r.
   (UserGroupStorePostgresEffectConstraints r) =>
diff --git a/libs/wire-subsystems/src/Wire/UserGroupSubsystem/Interpreter.hs b/libs/wire-subsystems/src/Wire/UserGroupSubsystem/Interpreter.hs
index 151152b12b..1af84cff5b 100644
--- a/libs/wire-subsystems/src/Wire/UserGroupSubsystem/Interpreter.hs
+++ b/libs/wire-subsystems/src/Wire/UserGroupSubsystem/Interpreter.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE RecordWildCards #-}
+
 module Wire.UserGroupSubsystem.Interpreter where
 
 import Control.Error (MaybeT (..))
@@ -12,6 +14,7 @@ import Imports
 import Polysemy
 import Polysemy.Error
 import Polysemy.Input (Input, input)
+import Wire.API.BackgroundJobs
 import Wire.API.Conversation qualified as Conversation
 import Wire.API.Error
 import Wire.API.Error.Brig qualified as E
@@ -23,10 +26,12 @@ import Wire.API.User
 import Wire.API.UserEvent
 import Wire.API.UserGroup
 import Wire.API.UserGroup.Pagination
+import Wire.BackgroundJobsPublisher
 import Wire.Error
 import Wire.GalleyAPIAccess (GalleyAPIAccess, internalGetConversation)
 import Wire.NotificationSubsystem
 import Wire.PaginationState
+import Wire.Sem.Random qualified as Random
 import Wire.TeamSubsystem
 import Wire.UserGroupStore (UserGroupPageRequest (..))
 import Wire.UserGroupStore qualified as Store
@@ -34,13 +39,15 @@ import Wire.UserGroupSubsystem (GroupSearch (..), UserGroupSubsystem (..))
 import Wire.UserSubsystem (UserSubsystem, getLocalUserProfiles, getUserTeam)
 
 interpretUserGroupSubsystem ::
-  ( Member UserSubsystem r,
+  ( Member Random.Random r,
+    Member UserSubsystem r,
     Member (Error UserGroupSubsystemError) r,
     Member Store.UserGroupStore r,
     Member (Input (Local ())) r,
     Member NotificationSubsystem r,
     Member TeamSubsystem r,
-    Member GalleyAPIAccess r
+    Member GalleyAPIAccess r,
+    Member BackgroundJobsPublisher r
   ) =>
   InterpreterFor UserGroupSubsystem r
 interpretUserGroupSubsystem = interpret $ \case
@@ -73,12 +80,14 @@ userGroupSubsystemErrorToHttpError =
     UserGroupChannelNotFound -> errorToWai @E.UserGroupChannelNotFound
 
 createUserGroup ::
-  ( Member UserSubsystem r,
+  ( Member Random.Random r,
+    Member UserSubsystem r,
     Member (Error UserGroupSubsystemError) r,
     Member Store.UserGroupStore r,
     Member (Input (Local ())) r,
     Member NotificationSubsystem r,
-    Member TeamSubsystem r
+    Member TeamSubsystem r,
+    Member BackgroundJobsPublisher r
   ) =>
   UserId ->
   NewUserGroup ->
@@ -99,6 +108,7 @@ createUserGroup creator newGroup = do
   pushNotifications
     [ mkEvent creator (UserGroupCreated ug.id_) admins
     ]
+  triggerSyncUserGroup team creator ug.id_
   pure ug
 
 getTeamAsAdmin ::
@@ -245,11 +255,13 @@ deleteGroup deleter groupId =
           throw UserGroupNotATeamAdmin
 
 addUser ::
-  ( Member UserSubsystem r,
+  ( Member Random.Random r,
+    Member UserSubsystem r,
     Member Store.UserGroupStore r,
     Member (Error UserGroupSubsystemError) r,
     Member NotificationSubsystem r,
-    Member TeamSubsystem r
+    Member TeamSubsystem r,
+    Member BackgroundJobsPublisher r
   ) =>
   UserId ->
   UserGroupId ->
@@ -265,13 +277,16 @@ addUser adder groupId addeeId = do
     pushNotifications
       [ mkEvent adder (UserGroupUpdated groupId) admins
       ]
+    triggerSyncUserGroup team adder groupId
 
 addUsers ::
-  ( Member UserSubsystem r,
+  ( Member Random.Random r,
+    Member UserSubsystem r,
     Member Store.UserGroupStore r,
     Member (Error UserGroupSubsystemError) r,
     Member NotificationSubsystem r,
-    Member TeamSubsystem r
+    Member TeamSubsystem r,
+    Member BackgroundJobsPublisher r
   ) =>
   UserId ->
   UserGroupId ->
@@ -291,12 +306,16 @@ addUsers adder groupId addeeIds = do
       [ mkEvent adder (UserGroupUpdated groupId) admins
       ]
 
+  triggerSyncUserGroup team adder groupId
+
 updateUsers ::
-  ( Member UserSubsystem r,
+  ( Member Random.Random r,
+    Member UserSubsystem r,
     Member Store.UserGroupStore r,
     Member (Error UserGroupSubsystemError) r,
     Member NotificationSubsystem r,
-    Member TeamSubsystem r
+    Member TeamSubsystem r,
+    Member BackgroundJobsPublisher r
   ) =>
   UserId ->
   UserGroupId ->
@@ -312,13 +331,16 @@ updateUsers updater groupId uids = do
   pushNotifications
     [ mkEvent updater (UserGroupUpdated groupId) admins
     ]
+  triggerSyncUserGroup team updater groupId
 
 removeUser ::
-  ( Member UserSubsystem r,
+  ( Member Random.Random r,
+    Member UserSubsystem r,
     Member Store.UserGroupStore r,
     Member (Error UserGroupSubsystemError) r,
     Member NotificationSubsystem r,
-    Member TeamSubsystem r
+    Member TeamSubsystem r,
+    Member BackgroundJobsPublisher r
   ) =>
   UserId ->
   UserGroupId ->
@@ -334,6 +356,7 @@ removeUser remover groupId removeeId = do
     pushNotifications
       [ mkEvent remover (UserGroupUpdated groupId) admins
       ]
+    triggerSyncUserGroup team remover groupId
 
 removeUserFromAllGroups ::
   ( Member Store.UserGroupStore r,
@@ -372,12 +395,14 @@ removeUserFromAllGroups uid tid = do
           }
 
 updateChannels ::
-  ( Member UserSubsystem r,
+  ( Member Random.Random r,
+    Member UserSubsystem r,
     Member Store.UserGroupStore r,
     Member (Error UserGroupSubsystemError) r,
     Member TeamSubsystem r,
     Member NotificationSubsystem r,
-    Member GalleyAPIAccess r
+    Member GalleyAPIAccess r,
+    Member BackgroundJobsPublisher r
   ) =>
   Bool ->
   UserId ->
@@ -392,11 +417,26 @@ updateChannels appendOnly performer groupId channelIds = do
     let meta = conv.metadata
     unless (meta.cnvmTeam == Just teamId && meta.cnvmGroupConvType == Just Conversation.Channel) $
       throw UserGroupChannelNotFound
+
   if appendOnly
     then Store.addUserGroupChannels groupId channelIds
     else Store.updateUserGroupChannels groupId channelIds
 
+  triggerSyncUserGroup teamId performer groupId
+
   admins <- fmap (^. TM.userId) . (^. teamMembers) <$> internalGetTeamAdmins teamId
   pushNotifications
     [ mkEvent performer (UserGroupUpdated groupId) admins
     ]
+
+triggerSyncUserGroup ::
+  ( Member Random.Random r,
+    Member BackgroundJobsPublisher r
+  ) =>
+  TeamId ->
+  UserId ->
+  UserGroupId ->
+  Sem r ()
+triggerSyncUserGroup teamId actor userGroupId = do
+  jobId <- Random.newId
+  publishJob jobId $ JobSyncUserGroup SyncUserGroup {..}
diff --git a/libs/wire-subsystems/test/unit/Wire/MockInterpreters/Random.hs b/libs/wire-subsystems/test/unit/Wire/MockInterpreters/Random.hs
index 6352edfe9d..870d813b0e 100644
--- a/libs/wire-subsystems/test/unit/Wire/MockInterpreters/Random.hs
+++ b/libs/wire-subsystems/test/unit/Wire/MockInterpreters/Random.hs
@@ -14,6 +14,7 @@ randomToStatefulStdGen = interpret $ \case
   Bytes n -> do
     fromShort <$> withStatefulGen (genShortByteString n)
   Uuid -> withStatefulGen random
+  NewId -> Id <$> withStatefulGen random
   ScimTokenId -> Id <$> withStatefulGen random
   LiftRandom m -> do
     seedInt <- withStatefulGen (random @Int)
diff --git a/libs/wire-subsystems/test/unit/Wire/MockInterpreters/UserGroupStore.hs b/libs/wire-subsystems/test/unit/Wire/MockInterpreters/UserGroupStore.hs
index 3a0746384b..c58f40bb9b 100644
--- a/libs/wire-subsystems/test/unit/Wire/MockInterpreters/UserGroupStore.hs
+++ b/libs/wire-subsystems/test/unit/Wire/MockInterpreters/UserGroupStore.hs
@@ -70,6 +70,7 @@ userGroupStoreTestInterpreter =
     RemoveUser gid uid -> removeUserImpl gid uid
     AddUserGroupChannels gid convIds -> updateUserGroupChannelsImpl True gid convIds
     UpdateUserGroupChannels gid convIds -> updateUserGroupChannelsImpl False gid convIds
+    GetUserGroupChannels tid gid -> getUserGroupChannelsImpl tid gid
     GetUserGroupIdsForUsers uids -> getUserGroupIdsForUsersImpl uids
 
 getUserGroupIdsForUsersImpl :: (UserGroupStoreInMemEffectConstraints r) => [UserId] -> Sem r (Map UserId [UserGroupId])
@@ -233,6 +234,17 @@ listUserGroupChannelsImpl gid =
   foldMap (fmap qUnqualified) . ((.channels) . snd <=< find ((== gid) . snd . fst) . Map.toList)
     <$> get @(Map (TeamId, UserGroupId) UserGroup)
 
+getUserGroupChannelsImpl ::
+  (UserGroupStoreInMemEffectConstraints r) =>
+  TeamId ->
+  UserGroupId ->
+  Sem r (Maybe (Vector ConvId))
+getUserGroupChannelsImpl tid gid = do
+  st <- get @UserGroupInMemState
+  pure $ case st Map.!? (tid, gid) of
+    Nothing -> Nothing
+    Just ug -> fmap (fmap qUnqualified) ug.channels
+
 ----------------------------------------------------------------------
 
 modifyUserGroupsGidOnly ::
diff --git a/libs/wire-subsystems/test/unit/Wire/UserGroupSubsystem/InterpreterSpec.hs b/libs/wire-subsystems/test/unit/Wire/UserGroupSubsystem/InterpreterSpec.hs
index aa35062d5c..c57863e262 100644
--- a/libs/wire-subsystems/test/unit/Wire/UserGroupSubsystem/InterpreterSpec.hs
+++ b/libs/wire-subsystems/test/unit/Wire/UserGroupSubsystem/InterpreterSpec.hs
@@ -39,9 +39,13 @@ import Wire.API.UserEvent
 import Wire.API.UserGroup
 import Wire.API.UserGroup.Pagination
 import Wire.Arbitrary
+import Wire.BackgroundJobsPublisher qualified as BackgroundJobsPublisher
+import Wire.BackgroundJobsPublisher.Null qualified as BackgroundJobsPublisher
 import Wire.GalleyAPIAccess
 import Wire.MockInterpreters as Mock
 import Wire.NotificationSubsystem
+import Wire.Sem.Random qualified as Random
+import Wire.Sem.Random.Null qualified as Random
 import Wire.TeamSubsystem
 import Wire.TeamSubsystem.GalleyAPI
 import Wire.UserGroupSubsystem
@@ -57,8 +61,10 @@ type AllDependencies =
     `Append` '[ Input (Local ()),
                 MockNow,
                 NotificationSubsystem,
+                BackgroundJobsPublisher.BackgroundJobsPublisher,
                 State [Push],
-                Error UserGroupSubsystemError
+                Error UserGroupSubsystemError,
+                Random.Random
               ]
 
 runDependenciesFailOnError :: (HasCallStack) => [User] -> Map TeamId [TeamMember] -> Sem AllDependencies (IO ()) -> IO ()
@@ -71,8 +77,10 @@ runDependencies ::
   Either UserGroupSubsystemError a
 runDependencies initialUsers initialTeams =
   run
+    . Random.randomToNull
     . runError
     . evalState mempty
+    . BackgroundJobsPublisher.interpretBackgroundJobsPublisherNoConfig
     . inMemoryNotificationSubsystemInterpreter
     . evalState defaultTime
     . runInputConst (toLocalUnsafe (Domain "example.com") ())
@@ -88,8 +96,10 @@ runDependenciesWithReturnState ::
   Either UserGroupSubsystemError ([Push], a)
 runDependenciesWithReturnState initialUsers initialTeams =
   run
+    . Random.randomToNull
     . runError
     . runState mempty
+    . BackgroundJobsPublisher.interpretBackgroundJobsPublisherNoConfig
     . inMemoryNotificationSubsystemInterpreter
     . evalState defaultTime
     . runInputConst (toLocalUnsafe (Domain "example.com") ())
diff --git a/libs/wire-subsystems/wire-subsystems.cabal b/libs/wire-subsystems/wire-subsystems.cabal
index a22d24a034..82604ed090 100644
--- a/libs/wire-subsystems/wire-subsystems.cabal
+++ b/libs/wire-subsystems/wire-subsystems.cabal
@@ -137,7 +137,9 @@ common common-all
     , servant
     , servant-client-core
     , servant-server
+    , singletons
     , sodium-crypto-sign
+    , ssl-util
     , statistics
     , stomp-queue
     , template
@@ -182,6 +184,13 @@ library
     Wire.AuthenticationSubsystem.Interpreter
     Wire.AuthenticationSubsystem.ZAuth
     Wire.AWS
+    Wire.BackendNotificationQueueAccess
+    Wire.BackendNotificationQueueAccess.RabbitMq
+    Wire.BackgroundJobsPublisher
+    Wire.BackgroundJobsPublisher.Null
+    Wire.BackgroundJobsPublisher.RabbitMQ
+    Wire.BackgroundJobsRunner
+    Wire.BackgroundJobsRunner.Interpreter
     Wire.BlockListStore
     Wire.BlockListStore.Cassandra
     Wire.BrigAPIAccess
@@ -192,6 +201,8 @@ library
     Wire.ConversationStore.Cassandra.Queries
     Wire.ConversationStore.MLS.Types
     Wire.ConversationStore.Postgres
+    Wire.ConversationSubsystem
+    Wire.ConversationSubsystem.Interpreter
     Wire.DeleteQueue
     Wire.DeleteQueue.InMemory
     Wire.DomainRegistrationStore
@@ -210,10 +221,13 @@ library
     Wire.EnterpriseLoginSubsystem.Null
     Wire.Error
     Wire.Events
+    Wire.ExternalAccess
+    Wire.ExternalAccess.External
     Wire.FederationAPIAccess
     Wire.FederationAPIAccess.Interpreter
     Wire.FederationConfigStore
     Wire.FederationConfigStore.Cassandra
+    Wire.FireAndForget
     Wire.GalleyAPIAccess
     Wire.GalleyAPIAccess.Rpc
     Wire.GundeckAPIAccess
@@ -248,6 +262,8 @@ library
     Wire.RateLimit
     Wire.RateLimit.Interpreter
     Wire.Rpc
+    Wire.ServiceStore
+    Wire.ServiceStore.Cassandra
     Wire.SessionStore
     Wire.SessionStore.Cassandra
     Wire.SparAPIAccess
diff --git a/services/background-worker/background-worker.cabal b/services/background-worker/background-worker.cabal
index 25079919e4..e3f7fde82e 100644
--- a/services/background-worker/background-worker.cabal
+++ b/services/background-worker/background-worker.cabal
@@ -16,6 +16,8 @@ library
     Wire.BackgroundWorker
     Wire.BackgroundWorker.Env
     Wire.BackgroundWorker.Health
+    Wire.BackgroundWorker.Jobs.Consumer
+    Wire.BackgroundWorker.Jobs.Registry
     Wire.BackgroundWorker.Options
     Wire.BackgroundWorker.Util
     Wire.DeadUserNotificationWatcher
@@ -35,18 +37,25 @@ library
     , bytestring-conversion
     , cassandra-util
     , containers
+    , data-timeout
     , exceptions
     , extended
+    , extra
+    , hasql-pool
     , HsOpenSSL
     , http-client
+    , http-client-openssl
     , http2-manager
     , imports
     , metrics-wai
     , monad-control
+    , polysemy
+    , polysemy-wire-zoo
     , prometheus-client
     , retry
     , servant-client
     , servant-server
+    , ssl-util
     , text
     , tinylog
     , transformers
@@ -56,6 +65,7 @@ library
     , wai-utilities
     , wire-api
     , wire-api-federation
+    , wire-subsystems
 
   default-extensions:
     AllowAmbiguousTypes
@@ -205,6 +215,7 @@ test-suite background-worker-test
     , wai-utilities
     , wire-api
     , wire-api-federation
+    , wire-subsystems
 
   default-extensions:
     AllowAmbiguousTypes
diff --git a/services/background-worker/background-worker.integration.yaml b/services/background-worker/background-worker.integration.yaml
index 60dc23a926..e1a470d3bc 100644
--- a/services/background-worker/background-worker.integration.yaml
+++ b/services/background-worker/background-worker.integration.yaml
@@ -8,12 +8,34 @@ federatorInternal:
   host: 127.0.0.1
   port: 8097
 
+brig:
+  host: 0.0.0.0
+  port: 8082
+
+gundeck:
+  host: 127.0.0.1
+  port: 8086
+
 cassandra:
   endpoint:
     host: 127.0.0.1
     port: 9042
   keyspace: gundeck_test
 
+cassandraBrig:
+  endpoint:
+    host: 127.0.0.1
+    port: 9042
+  keyspace: brig_test
+
+cassandraGalley:
+  endpoint:
+    host: 127.0.0.1
+    port: 9042
+  keyspace: galley_test
+
+domain: example.org
+
 rabbitmq:
   host: 127.0.0.1
   port: 5671
@@ -28,3 +50,25 @@ backendNotificationPusher:
   pushBackoffMinWait: 1000 # 1ms
   pushBackoffMaxWait: 1000000 # 1s
   remotesRefreshInterval: 10000 # 10ms
+
+# Background jobs consumer configuration for integration
+backgroundJobs:
+  concurrency: 4
+  jobTimeout: 5
+  maxAttempts: 3
+
+postgresql:
+  host: 127.0.0.1
+  port: "5432"
+  user: wire-server
+  dbname: backendA
+  password: posty-the-gres
+
+postgresqlPool:
+  size: 20
+  acquisitionTimeout: 10s
+  agingTimeout: 1d
+  idlenessTimeout: 10m
+
+postgresMigration:
+  conversation: postgresql
diff --git a/services/background-worker/default.nix b/services/background-worker/default.nix
index 7ef4b6ab45..9c4f5614c2 100644
--- a/services/background-worker/default.nix
+++ b/services/background-worker/default.nix
@@ -11,13 +11,17 @@
 , cassandra-util
 , containers
 , data-default
+, data-timeout
 , exceptions
 , extended
+, extra
 , federator
 , gitignoreSource
+, hasql-pool
 , HsOpenSSL
 , hspec
 , http-client
+, http-client-openssl
 , http-media
 , http-types
 , http2-manager
@@ -25,6 +29,8 @@
 , lib
 , metrics-wai
 , monad-control
+, polysemy
+, polysemy-wire-zoo
 , prometheus-client
 , QuickCheck
 , retry
@@ -32,6 +38,7 @@
 , servant-client
 , servant-client-core
 , servant-server
+, ssl-util
 , text
 , tinylog
 , transformers
@@ -42,6 +49,7 @@
 , wai-utilities
 , wire-api
 , wire-api-federation
+, wire-subsystems
 }:
 mkDerivation {
   pname = "background-worker";
@@ -57,18 +65,25 @@ mkDerivation {
     bytestring-conversion
     cassandra-util
     containers
+    data-timeout
     exceptions
     extended
+    extra
+    hasql-pool
     HsOpenSSL
     http-client
+    http-client-openssl
     http2-manager
     imports
     metrics-wai
     monad-control
+    polysemy
+    polysemy-wire-zoo
     prometheus-client
     retry
     servant-client
     servant-server
+    ssl-util
     text
     tinylog
     transformers
@@ -78,6 +93,7 @@ mkDerivation {
     wai-utilities
     wire-api
     wire-api-federation
+    wire-subsystems
   ];
   executableHaskellDepends = [ HsOpenSSL imports types-common ];
   testHaskellDepends = [
@@ -109,6 +125,7 @@ mkDerivation {
     wai-utilities
     wire-api
     wire-api-federation
+    wire-subsystems
   ];
   description = "Runs background work";
   license = lib.licenses.agpl3Only;
diff --git a/services/background-worker/src/Wire/BackgroundWorker.hs b/services/background-worker/src/Wire/BackgroundWorker.hs
index e6110fb438..b1aeb9789f 100644
--- a/services/background-worker/src/Wire/BackgroundWorker.hs
+++ b/services/background-worker/src/Wire/BackgroundWorker.hs
@@ -14,6 +14,7 @@ import Util.Options
 import Wire.BackendNotificationPusher qualified as BackendNotificationPusher
 import Wire.BackgroundWorker.Env
 import Wire.BackgroundWorker.Health qualified as Health
+import Wire.BackgroundWorker.Jobs.Consumer qualified as Jobs
 import Wire.BackgroundWorker.Options
 import Wire.DeadUserNotificationWatcher qualified as DeadUserNotificationWatcher
 
@@ -23,16 +24,20 @@ run opts = do
   let amqpEP = either id demoteOpts opts.rabbitmq.unRabbitMqOpts
   cleanupBackendNotifPusher <-
     runAppT env $
-      withNamedLogger "backend-notifcation-pusher" $
+      withNamedLogger "backend-notification-pusher" $
         BackendNotificationPusher.startWorker amqpEP
   cleanupDeadUserNotifWatcher <-
     runAppT env $
       withNamedLogger "dead-user-notification-watcher" $
         DeadUserNotificationWatcher.startWorker amqpEP
+  cleanupJobs <-
+    runAppT env $
+      withNamedLogger "background-job-consumer" $
+        Jobs.startWorker amqpEP
   let -- cleanup will run in a new thread when the signal is caught, so we need to use IORefs and
       -- specific exception types to message threads to clean up
       cleanup = do
-        concurrently_ cleanupDeadUserNotifWatcher cleanupBackendNotifPusher
+        concurrently_ cleanupDeadUserNotifWatcher (concurrently_ cleanupBackendNotifPusher cleanupJobs)
   let server = defaultServer (T.unpack $ opts.backgroundWorker.host) opts.backgroundWorker.port env.logger
   let settings = newSettings server
   -- Additional cleanup when shutting down via signals.
diff --git a/services/background-worker/src/Wire/BackgroundWorker/Env.hs b/services/background-worker/src/Wire/BackgroundWorker/Env.hs
index 93711e9d9b..d843b5e737 100644
--- a/services/background-worker/src/Wire/BackgroundWorker/Env.hs
+++ b/services/background-worker/src/Wire/BackgroundWorker/Env.hs
@@ -8,9 +8,13 @@ import Cassandra.Util (defInitCassandra)
 import Control.Monad.Base
 import Control.Monad.Catch
 import Control.Monad.Trans.Control
+import Data.Domain (Domain)
 import Data.Map.Strict qualified as Map
 import HTTP2.Client.Manager
+import Hasql.Pool qualified as HasqlPool
+import Hasql.Pool.Extended (initPostgresPool)
 import Imports
+import Network.AMQP qualified as Q
 import Network.AMQP.Extended
 import Network.HTTP.Client
 import Network.RabbitMqAdmin qualified as RabbitMqAdmin
@@ -23,6 +27,7 @@ import System.Logger.Class (Logger, MonadLogger (..))
 import System.Logger.Extended qualified as Log
 import Util.Options
 import Wire.BackgroundWorker.Options
+import Wire.ConversationStore (PostgresMigrationOpts)
 
 type IsWorking = Bool
 
@@ -30,12 +35,14 @@ type IsWorking = Bool
 data Worker
   = BackendNotificationPusher
   | DeadUserNotificationWatcher
+  | BackgroundJobConsumer
   deriving (Eq, Ord)
 
 workerName :: Worker -> Text
 workerName = \case
   BackendNotificationPusher -> "backend-notification-pusher"
   DeadUserNotificationWatcher -> "dead-user-notification-watcher"
+  BackgroundJobConsumer -> "background-job-consumer"
 
 data Env = Env
   { http2Manager :: Http2Manager,
@@ -47,9 +54,20 @@ data Env = Env
     defederationTimeout :: ResponseTimeout,
     backendNotificationMetrics :: BackendNotificationMetrics,
     backendNotificationsConfig :: BackendNotificationsConfig,
+    backgroundJobsConfig :: BackgroundJobsConfig,
     workerRunningGauge :: Vector Text Gauge,
     statuses :: IORef (Map Worker IsWorking),
-    cassandra :: ClientState
+    gundeckCassandra :: ClientState,
+    brigCassandra :: ClientState,
+    galleyCassandra :: ClientState,
+    hasqlPool :: HasqlPool.Pool,
+    -- Dedicated AMQP channels per concern
+    amqpJobsPublisherChannel :: MVar Q.Channel,
+    amqpBackendNotificationsChannel :: MVar Q.Channel,
+    domain :: Domain,
+    postgresMigration :: PostgresMigrationOpts,
+    gundeckEndpoint :: Endpoint,
+    brigEndpoint :: Endpoint
   }
 
 data BackendNotificationMetrics = BackendNotificationMetrics
@@ -72,7 +90,9 @@ mkWorkerRunningGauge =
 mkEnv :: Opts -> IO Env
 mkEnv opts = do
   logger <- Log.mkLogger opts.logLevel Nothing opts.logFormat
-  cassandra <- defInitCassandra opts.cassandra logger
+  gundeckCassandra <- defInitCassandra opts.cassandra logger
+  brigCassandra <- defInitCassandra opts.cassandraBrig logger
+  galleyCassandra <- defInitCassandra opts.cassandraGalley logger
   http2Manager <- initHttp2Manager
   httpManager <- newManager defaultManagerSettings
   let federatorInternal = opts.federatorInternal
@@ -86,11 +106,24 @@ mkEnv opts = do
   statuses <-
     newIORef $
       Map.fromList
-        [ (BackendNotificationPusher, False)
+        [ (BackendNotificationPusher, False),
+          (BackgroundJobConsumer, False)
         ]
   backendNotificationMetrics <- mkBackendNotificationMetrics
   let backendNotificationsConfig = opts.backendNotificationPusher
+      backgroundJobsConfig = opts.backgroundJobs
+      domain = opts.domain
+      postgresMigration = opts.postgresMigration
+      brigEndpoint = opts.brig
+      gundeckEndpoint = opts.gundeck
   workerRunningGauge <- mkWorkerRunningGauge
+  hasqlPool <- initPostgresPool opts.postgresqlPool opts.postgresql opts.postgresqlPassword
+  amqpJobsPublisherChannel <-
+    mkRabbitMqChannelMVar logger (Just "background-worker-jobs-publisher") $
+      either id demoteOpts opts.rabbitmq.unRabbitMqOpts
+  amqpBackendNotificationsChannel <-
+    mkRabbitMqChannelMVar logger (Just "background-worker-backend-notifications") $
+      either id demoteOpts opts.rabbitmq.unRabbitMqOpts
   pure Env {..}
 
 initHttp2Manager :: IO Http2Manager
diff --git a/services/background-worker/src/Wire/BackgroundWorker/Jobs/Consumer.hs b/services/background-worker/src/Wire/BackgroundWorker/Jobs/Consumer.hs
new file mode 100644
index 0000000000..4ab007cca8
--- /dev/null
+++ b/services/background-worker/src/Wire/BackgroundWorker/Jobs/Consumer.hs
@@ -0,0 +1,121 @@
+{-# LANGUAGE RecordWildCards #-}
+
+module Wire.BackgroundWorker.Jobs.Consumer (startWorker, BackgroundJobsMetrics (..)) where
+
+import Control.Concurrent.Timeout qualified as Timeout
+import Control.Retry
+import Data.Aeson qualified as Aeson
+import Data.Range (Range (fromRange))
+import Data.Timeout
+import Imports
+import Network.AMQP qualified as Q
+import Network.AMQP.Extended
+import Network.AMQP.Lifted qualified as QL
+import Prometheus
+import System.Logger.Class qualified as Log
+import System.Time.Extra (duration)
+import UnliftIO
+import Wire.API.BackgroundJobs
+import Wire.BackgroundWorker.Env
+import Wire.BackgroundWorker.Jobs.Registry
+import Wire.BackgroundWorker.Options
+import Wire.BackgroundWorker.Util (CleanupAction)
+
+data BackgroundJobsMetrics = BackgroundJobsMetrics
+  { workersBusy :: Gauge,
+    concurrencyConfigured :: Gauge,
+    jobsReceived :: Vector Text Counter,
+    jobsStarted :: Vector Text Counter,
+    jobsSucceeded :: Vector Text Counter,
+    jobsFailed :: Vector Text Counter,
+    jobsInvalid :: Vector Text Counter,
+    jobsRedelivered :: Vector Text Counter,
+    jobDuration :: Vector Text Histogram
+  }
+
+mkMetrics :: IO BackgroundJobsMetrics
+mkMetrics = do
+  workersBusy <- register (gauge $ Info {metricName = "wire_background_jobs_workers_busy", metricHelp = "In-flight background jobs"})
+  concurrencyConfigured <- register (gauge $ Info {metricName = "wire_background_jobs_concurrency_configured", metricHelp = "Configured concurrency for this process"})
+  jobsReceived <- register (vector "job_type" $ counter $ Info "wire_background_jobs_received_total" "Jobs received")
+  jobsStarted <- register (vector "job_type" $ counter $ Info "wire_background_jobs_started_total" "Jobs started")
+  jobsSucceeded <- register (vector "job_type" $ counter $ Info "wire_background_jobs_succeeded_total" "Jobs succeeded")
+  jobsFailed <- register (vector "job_type" $ counter $ Info "wire_background_jobs_failed_total" "Jobs failed")
+  jobsInvalid <- register (vector "job_type" $ counter $ Info "wire_background_jobs_invalid_total" "Invalid jobs received")
+  jobsRedelivered <- register (vector "job_type" $ counter $ Info "wire_background_jobs_redelivered_total" "Jobs marked redelivered by broker")
+  jobDuration <- register (vector "job_type" $ histogram (Info "wire_background_jobs_duration_seconds" "Job duration seconds") defaultBuckets)
+  pure BackgroundJobsMetrics {..}
+
+startWorker :: AmqpEndpoint -> AppT IO CleanupAction
+startWorker rabbitmqOpts = do
+  env <- ask
+  let cfg = env.backgroundJobsConfig
+  metrics <- liftIO mkMetrics
+  markAsNotWorking BackgroundJobConsumer
+  void . async . liftIO $
+    openConnectionWithRetries env.logger rabbitmqOpts (Just "background-job-consumer") $
+      RabbitMqHooks
+        { onNewChannel = \chan -> do
+            -- declare queue and set prefetch to concurrency
+            ensureBackgroundJobsQueue chan
+            Q.qos chan 0 (fromIntegral $ fromRange cfg.concurrency) False
+            -- set gauges
+            setGauge metrics.concurrencyConfigured (fromIntegral $ fromRange cfg.concurrency)
+            -- start consuming with manual ack and keep the channel alive
+            void $ QL.consumeMsgs chan backgroundJobsQueueName Q.Ack (void . runAppT env . handleDelivery metrics cfg)
+            runAppT env $ markAsWorking BackgroundJobConsumer
+            forever $ threadDelay maxBound,
+          onChannelException = \_ -> do
+            -- mark not working; TODO: only log unexpected exceptions
+            runAppT env $ markAsNotWorking BackgroundJobConsumer,
+          onConnectionClose =
+            runAppT env $ do
+              markAsNotWorking BackgroundJobConsumer
+              Log.info $ Log.msg (Log.val "RabbitMQ connection closed for background job consumer")
+        }
+  pure $ runAppT env $ cleanup
+  where
+    cleanup :: AppT IO ()
+    cleanup = do
+      -- nothing to close explicitly; the AMQP helper closes channel/connection on shutdown
+      Log.info $ Log.msg (Log.val "Background job consumer cleanup")
+      markAsNotWorking BackgroundJobConsumer
+
+handleDelivery :: BackgroundJobsMetrics -> BackgroundJobsConfig -> (Q.Message, Q.Envelope) -> AppT IO ()
+handleDelivery metrics cfg (msg, env) = do
+  case Aeson.eitherDecode @Job (Q.msgBody msg) of
+    Left err -> do
+      withLabel metrics.jobsInvalid "invalid" incCounter
+      Log.err $ Log.msg (Log.val "Invalid background job JSON") . Log.field "error" err
+      Timeout.threadDelay (200 # MilliSecond) -- avoid tight redelivery loop
+      liftIO $ Q.rejectEnv env True
+    Right job -> do
+      let lbl = jobPayloadLabel job.payload
+      when (Q.envRedelivered env) $ withLabel metrics.jobsRedelivered lbl incCounter
+      withLabel metrics.jobsReceived lbl incCounter
+      UnliftIO.bracket_ (incGauge metrics.workersBusy) (decGauge metrics.workersBusy) $ do
+        outcome <- runAttempts lbl job
+        case outcome of
+          Right () -> do
+            withLabel metrics.jobsSucceeded lbl incCounter
+            liftIO $ Q.ackEnv env
+          Left e -> do
+            withLabel metrics.jobsFailed lbl incCounter
+            Log.err $ Log.msg (Log.val "Background job failed after retries") . Log.field "error" e
+            liftIO $ Q.rejectEnv env False
+  where
+    runAttempts :: Text -> Job -> AppT IO (Either Text ())
+    runAttempts lbl job = do
+      let retries = max 0 (fromRange cfg.maxAttempts - 1)
+          policy = limitRetries retries <> fullJitterBackoff 100000 -- 100ms base
+      retrying policy shouldRetry $ \_rs -> do
+        withLabel metrics.jobsStarted lbl incCounter
+        (dur, r) <-
+          duration $
+            fromMaybe (Left "job timeout")
+              <$> timeout (fromRange cfg.jobTimeout * 1000000) (dispatchJob job)
+        withLabel metrics.jobDuration lbl (`observe` dur)
+        pure r
+      where
+        shouldRetry _ (Right _) = pure False
+        shouldRetry _ (Left _) = pure True
diff --git a/services/background-worker/src/Wire/BackgroundWorker/Jobs/Registry.hs b/services/background-worker/src/Wire/BackgroundWorker/Jobs/Registry.hs
new file mode 100644
index 0000000000..2e52e12570
--- /dev/null
+++ b/services/background-worker/src/Wire/BackgroundWorker/Jobs/Registry.hs
@@ -0,0 +1,128 @@
+module Wire.BackgroundWorker.Jobs.Registry
+  ( dispatchJob,
+  )
+where
+
+import Data.ByteString.Conversion (toByteString')
+import Data.Id
+import Data.Qualified
+import Data.Text qualified as T
+import Hasql.Pool (UsageError)
+import Imports
+import Network.HTTP.Client
+import Network.HTTP.Client.OpenSSL
+import OpenSSL.EVP.Digest
+import OpenSSL.Session as Ssl
+import Polysemy
+import Polysemy.Async (asyncToIOFinal)
+import Polysemy.Error
+import Polysemy.Input
+import Polysemy.TinyLog qualified as P
+import Ssl.Util
+import System.Logger as Logger
+import Wire.API.BackgroundJobs (Job (..))
+import Wire.API.Federation.Error (FederationError)
+import Wire.BackendNotificationQueueAccess.RabbitMq qualified as BackendNotificationQueueAccess
+import Wire.BackgroundJobsPublisher.RabbitMQ (interpretBackgroundJobsPublisherRabbitMQ)
+import Wire.BackgroundJobsRunner (runJob)
+import Wire.BackgroundJobsRunner.Interpreter hiding (runJob)
+import Wire.BackgroundWorker.Env (AppT, Env (..))
+import Wire.BrigAPIAccess.Rpc
+import Wire.ConversationStore
+import Wire.ConversationStore.Cassandra (interpretConversationStoreToCassandra)
+import Wire.ConversationStore.Postgres (interpretConversationStoreToPostgres)
+import Wire.ConversationSubsystem.Interpreter (interpretConversationSubsystem)
+import Wire.ExternalAccess.External
+import Wire.FireAndForget (interpretFireAndForget)
+import Wire.GundeckAPIAccess
+import Wire.NotificationSubsystem.Interpreter
+import Wire.ParseException
+import Wire.Rpc
+import Wire.Sem.Delay (runDelay)
+import Wire.Sem.Now.IO (nowToIO)
+import Wire.Sem.Random.IO (randomToIO)
+import Wire.ServiceStore.Cassandra (interpretServiceStoreToCassandra)
+import Wire.UserGroupStore.Postgres (interpretUserGroupStoreToPostgres)
+import Wire.UserStore.Cassandra (interpretUserStoreCassandra)
+
+dispatchJob :: Job -> AppT IO (Either Text ())
+dispatchJob job = do
+  env <- ask @Env
+  extEnv <- liftIO initExtEnv
+  liftIO $ runInterpreters env extEnv $ runJob job
+  where
+    convStoreInterpreter env =
+      case env.postgresMigration.conversation of
+        CassandraStorage -> interpretConversationStoreToCassandra env.galleyCassandra
+        PostgresqlStorage -> interpretConversationStoreToPostgres
+    runInterpreters env extEnv = do
+      runFinal @IO
+        . embedToFinal @IO
+        . asyncToIOFinal
+        . runDelay
+        . runError
+        . mapError @FederationError (T.pack . show)
+        . mapError @UsageError (T.pack . show)
+        . mapError @ParseException (T.pack . show)
+        . interpretTinyLog env job.requestId
+        . runInputConst env.hasqlPool
+        . runInputConst (toLocalUnsafe env.domain ())
+        . interpretServiceStoreToCassandra env.brigCassandra
+        . interpretUserStoreCassandra env.brigCassandra
+        . interpretUserGroupStoreToPostgres
+        . runInputSem (readMVar env.amqpJobsPublisherChannel)
+        . interpretBackgroundJobsPublisherRabbitMQ job.requestId
+        . nowToIO
+        . randomToIO
+        . interpretFireAndForget
+        . BackendNotificationQueueAccess.interpretBackendNotificationQueueAccess (Just $ backendQueueEnv env)
+        . convStoreInterpreter env
+        . runRpcWithHttp env.httpManager job.requestId
+        . runGundeckAPIAccess env.gundeckEndpoint
+        -- FUTUREWORK: Currently the brig access effect is needed for the interpreter of ExternalAccess.
+        -- At the time of implementation the only function used from ExternalAccess is deliverAsync, which will not call brig access.
+        -- However, to prevent the background worker to require HTTP access to brig, we should consider refactoring this at some point.
+        . interpretBrigAccess env.brigEndpoint
+        . interpretExternalAccess extEnv
+        . runNotificationSubsystemGundeck (defaultNotificationSubsystemConfig job.requestId)
+        . interpretConversationSubsystem
+        . interpretBackgroundJobsRunner
+
+    backendQueueEnv env =
+      BackendNotificationQueueAccess.Env
+        { channelMVar = env.amqpBackendNotificationsChannel,
+          logger = env.logger,
+          local = toLocalUnsafe env.domain (),
+          requestId = job.requestId
+        }
+
+interpretTinyLog ::
+  (Member (Embed IO) r) =>
+  Env ->
+  RequestId ->
+  Sem (P.TinyLog ': r) a ->
+  Sem r a
+interpretTinyLog e reqId = interpret $ \case
+  P.Log l m -> Logger.log e.logger l ((("request" .=) . unRequestId) reqId . m)
+
+initExtEnv :: IO ExtEnv
+initExtEnv = do
+  ctx <- Ssl.context
+  Ssl.contextSetVerificationMode ctx Ssl.VerifyNone
+  Ssl.contextAddOption ctx SSL_OP_NO_SSLv2
+  Ssl.contextAddOption ctx SSL_OP_NO_SSLv3
+  Ssl.contextAddOption ctx SSL_OP_NO_TLSv1
+  Ssl.contextSetCiphers ctx rsaCiphers
+  Ssl.contextSetDefaultVerifyPaths ctx
+  mgr <-
+    newManager
+      (opensslManagerSettings (pure ctx))
+        { managerResponseTimeout = responseTimeoutMicro 10000000,
+          managerConnCount = 100
+        }
+  Just sha <- getDigestByName "SHA256"
+  pure $ ExtEnv (mgr, mkVerify sha)
+  where
+    mkVerify sha fprs =
+      let pinset = map toByteString' fprs
+       in verifyRsaFingerprint sha pinset
diff --git a/services/background-worker/src/Wire/BackgroundWorker/Options.hs b/services/background-worker/src/Wire/BackgroundWorker/Options.hs
index f9055d89e0..a27bb50bdd 100644
--- a/services/background-worker/src/Wire/BackgroundWorker/Options.hs
+++ b/services/background-worker/src/Wire/BackgroundWorker/Options.hs
@@ -1,25 +1,41 @@
 module Wire.BackgroundWorker.Options where
 
 import Data.Aeson
+import Data.Domain (Domain)
+import Data.Range (Range)
+import GHC.Generics
+import Hasql.Pool.Extended (PoolConfig)
 import Imports
 import Network.AMQP.Extended
 import System.Logger.Extended
 import Util.Options
+import Wire.ConversationStore (PostgresMigrationOpts)
 
 data Opts = Opts
   { logLevel :: !Level,
     logFormat :: !(Maybe (Last LogFormat)),
     backgroundWorker :: !Endpoint,
     federatorInternal :: !Endpoint,
+    brig :: Endpoint,
+    gundeck :: Endpoint,
     rabbitmq :: !RabbitMqOpts,
     -- | Seconds, Nothing for no timeout
     defederationTimeout :: Maybe Int,
     backendNotificationPusher :: BackendNotificationsConfig,
-    cassandra :: CassandraOpts
+    cassandra :: CassandraOpts,
+    cassandraBrig :: CassandraOpts,
+    cassandraGalley :: CassandraOpts,
+    backgroundJobs :: BackgroundJobsConfig,
+    -- | Postgresql settings, the key values must be in libpq format.
+    -- https://www.postgresql.org/docs/17/libpq-connect.html#LIBPQ-PARAMKEYWORDS
+    postgresql :: !(Map Text Text),
+    postgresqlPassword :: !(Maybe FilePathSecrets),
+    postgresqlPool :: !PoolConfig,
+    postgresMigration :: !PostgresMigrationOpts,
+    domain :: Domain
   }
   deriving (Show, Generic)
-
-instance FromJSON Opts
+  deriving (FromJSON) via Generically Opts
 
 data BackendNotificationsConfig = BackendNotificationsConfig
   { -- | Minimum amount of time (in microseconds) to wait before doing the first
@@ -36,8 +52,7 @@ data BackendNotificationsConfig = BackendNotificationsConfig
     remotesRefreshInterval :: Int
   }
   deriving (Show, Generic)
-
-instance FromJSON BackendNotificationsConfig
+  deriving (FromJSON) via Generically BackendNotificationsConfig
 
 newtype RabbitMqOpts = RabbitMqOpts {unRabbitMqOpts :: Either AmqpEndpoint RabbitMqAdminOpts}
   deriving (Show)
@@ -48,3 +63,14 @@ instance FromJSON RabbitMqOpts where
       <$> ( (Right <$> parseJSON v)
               <|> (Left <$> parseJSON v)
           )
+
+data BackgroundJobsConfig = BackgroundJobsConfig
+  { -- | Maximum parallel jobs processed by this process
+    concurrency :: Range 1 1000 Int,
+    -- | Per-attempt timeout (seconds)
+    jobTimeout :: Range 1 1000 Int,
+    -- | Total attempts including first run
+    maxAttempts :: Range 1 1000 Int
+  }
+  deriving (Show, Generic)
+  deriving (FromJSON) via Generically BackgroundJobsConfig
diff --git a/services/background-worker/src/Wire/DeadUserNotificationWatcher.hs b/services/background-worker/src/Wire/DeadUserNotificationWatcher.hs
index 802f89eda6..d4bb3c1d0a 100644
--- a/services/background-worker/src/Wire/DeadUserNotificationWatcher.hs
+++ b/services/background-worker/src/Wire/DeadUserNotificationWatcher.hs
@@ -34,7 +34,7 @@ startConsumer chan = do
   env <- ask
   markAsWorking DeadUserNotificationWatcher
 
-  cassandra <- asks (.cassandra)
+  cassandra <- asks (.gundeckCassandra)
 
   void . lift $
     Q.declareQueue
diff --git a/services/background-worker/test/Test/Wire/BackendNotificationPusherSpec.hs b/services/background-worker/test/Test/Wire/BackendNotificationPusherSpec.hs
index 9e88cbe9f0..6d9f12be8d 100644
--- a/services/background-worker/test/Test/Wire/BackendNotificationPusherSpec.hs
+++ b/services/background-worker/test/Test/Wire/BackendNotificationPusherSpec.hs
@@ -51,6 +51,7 @@ import Wire.BackendNotificationPusher
 import Wire.BackgroundWorker.Env
 import Wire.BackgroundWorker.Options
 import Wire.BackgroundWorker.Util
+import Wire.ConversationStore
 
 spec :: Spec
 spec = do
@@ -322,14 +323,29 @@ spec = do
           ]
       logger <- Logger.new Logger.defSettings
       httpManager <- newManager defaultManagerSettings
-      let cassandra = undefined
-      let federatorInternal = Endpoint "localhost" 8097
+      let gundeckCassandra = undefined
+          brigCassandra = undefined
+          galleyCassandra = undefined
+          federatorInternal = Endpoint "localhost" 8097
           http2Manager = undefined
           statuses = undefined
           rabbitmqAdminClient = Just $ mockRabbitMqAdminClient mockAdmin
           rabbitmqVHost = "test-vhost"
           defederationTimeout = responseTimeoutNone
           backendNotificationsConfig = BackendNotificationsConfig 1000 500000 1000
+          backgroundJobsConfig =
+            BackgroundJobsConfig
+              { concurrency = toRange (Proxy @1),
+                jobTimeout = toRange (Proxy @100),
+                maxAttempts = toRange (Proxy @3)
+              }
+          hasqlPool = undefined
+          amqpJobsPublisherChannel = undefined
+          amqpBackendNotificationsChannel = undefined
+          domain = Domain "local"
+          postgresMigration = PostgresMigrationOpts CassandraStorage
+          gundeckEndpoint = undefined
+          brigEndpoint = undefined
 
       backendNotificationMetrics <- mkBackendNotificationMetrics
       workerRunningGauge <- mkWorkerRunningGauge
@@ -340,15 +356,30 @@ spec = do
     it "should retry fetching domains if a request fails" $ do
       mockAdmin <- newMockRabbitMqAdmin True ["backend-notifications.foo.example"]
       logger <- Logger.new Logger.defSettings
-      let cassandra = undefined
       httpManager <- newManager defaultManagerSettings
       let federatorInternal = Endpoint "localhost" 8097
+          gundeckCassandra = undefined
+          brigCassandra = undefined
+          galleyCassandra = undefined
           http2Manager = undefined
           statuses = undefined
           rabbitmqAdminClient = Just $ mockRabbitMqAdminClient mockAdmin
           rabbitmqVHost = "test-vhost"
           defederationTimeout = responseTimeoutNone
           backendNotificationsConfig = BackendNotificationsConfig 1000 500000 1000
+          backgroundJobsConfig =
+            BackgroundJobsConfig
+              { concurrency = toRange (Proxy @1),
+                jobTimeout = toRange (Proxy @100),
+                maxAttempts = toRange (Proxy @3)
+              }
+          hasqlPool = undefined
+          amqpJobsPublisherChannel = undefined
+          amqpBackendNotificationsChannel = undefined
+          domain = Domain "local"
+          postgresMigration = PostgresMigrationOpts CassandraStorage
+          gundeckEndpoint = undefined
+          brigEndpoint = undefined
       backendNotificationMetrics <- mkBackendNotificationMetrics
       workerRunningGauge <- mkWorkerRunningGauge
       domainsThread <- async $ runAppT Env {..} $ getRemoteDomains (fromJust rabbitmqAdminClient)
diff --git a/services/background-worker/test/Test/Wire/Util.hs b/services/background-worker/test/Test/Wire/Util.hs
index cb4eeef5f9..dc2dfac958 100644
--- a/services/background-worker/test/Test/Wire/Util.hs
+++ b/services/background-worker/test/Test/Wire/Util.hs
@@ -2,19 +2,26 @@
 
 module Test.Wire.Util where
 
+import Data.Domain (Domain (Domain))
+import Data.Proxy
+import Data.Range
 import Imports
-import Network.HTTP.Client
+import Network.HTTP.Client hiding (Proxy)
 import System.Logger.Class qualified as Logger
 import Util.Options (Endpoint (..))
 import Wire.BackgroundWorker.Env hiding (federatorInternal)
 import Wire.BackgroundWorker.Env qualified as E
 import Wire.BackgroundWorker.Options
+import Wire.ConversationStore
 
 testEnv :: IO Env
 testEnv = do
   http2Manager <- initHttp2Manager
   logger <- Logger.new Logger.defSettings
-  let cassandra = undefined
+  let gundeckCassandra = undefined
+      brigCassandra = undefined
+      galleyCassandra = undefined
+      postgresMigration = PostgresMigrationOpts CassandraStorage
   statuses <- newIORef mempty
   backendNotificationMetrics <- mkBackendNotificationMetrics
   workerRunningGauge <- mkWorkerRunningGauge
@@ -24,6 +31,18 @@ testEnv = do
       rabbitmqVHost = undefined
       defederationTimeout = responseTimeoutNone
       backendNotificationsConfig = BackendNotificationsConfig 1000 500000 1000
+      backgroundJobsConfig =
+        BackgroundJobsConfig
+          { concurrency = toRange (Proxy @1),
+            jobTimeout = toRange (Proxy @100),
+            maxAttempts = toRange (Proxy @3)
+          }
+      hasqlPool = undefined
+      amqpJobsPublisherChannel = undefined
+      amqpBackendNotificationsChannel = undefined
+      domain = Domain "local"
+      gundeckEndpoint = undefined
+      brigEndpoint = undefined
   pure Env {..}
 
 runTestAppT :: AppT IO a -> Int -> IO a
diff --git a/services/brig/src/Brig/App.hs b/services/brig/src/Brig/App.hs
index 811e6930e2..3ce647b469 100644
--- a/services/brig/src/Brig/App.hs
+++ b/services/brig/src/Brig/App.hs
@@ -71,6 +71,7 @@ module Brig.App
     disabledVersionsLens,
     enableSFTFederationLens,
     rateLimitEnvLens,
+    amqpJobsPublisherChannelLens,
     initZAuth,
     initLogger,
     initPostgresPool,
@@ -218,7 +219,8 @@ data Env = Env
     rabbitmqChannel :: Maybe (MVar Q.Channel),
     disabledVersions :: Set Version,
     enableSFTFederation :: Maybe Bool,
-    rateLimitEnv :: RateLimitEnv
+    rateLimitEnv :: RateLimitEnv,
+    amqpJobsPublisherChannel :: Maybe (MVar Q.Channel)
   }
 
 makeLensesWith (lensRules & lensField .~ suffixNamer) ''Env
@@ -280,6 +282,7 @@ newEnv opts = do
   idxEnv <- mkIndexEnv opts.elasticsearch lgr (Opt.galley opts) mgr
   rateLimitEnv <- newRateLimitEnv opts.settings.passwordHashingRateLimit
   hasqlPool <- initPostgresPool opts.postgresqlPool opts.postgresql opts.postgresqlPassword
+  amqpJobsPublisherChannel <- traverse (Q.mkRabbitMqChannelMVar lgr (Just "brig")) opts.rabbitmq
   pure $!
     Env
       { cargohold = mkEndpoint $ opts.cargohold,
@@ -319,7 +322,8 @@ newEnv opts = do
         rabbitmqChannel = rabbitChan,
         disabledVersions = allDisabledVersions,
         enableSFTFederation = opts.multiSFT,
-        rateLimitEnv
+        rateLimitEnv,
+        amqpJobsPublisherChannel
       }
   where
     emailConn _ (Opt.EmailAWS aws) = pure (Just aws, Nothing)
diff --git a/services/brig/src/Brig/CanonicalInterpreter.hs b/services/brig/src/Brig/CanonicalInterpreter.hs
index 6e968f75ae..948b5c7f62 100644
--- a/services/brig/src/Brig/CanonicalInterpreter.hs
+++ b/services/brig/src/Brig/CanonicalInterpreter.hs
@@ -45,6 +45,8 @@ import Wire.AppSubsystem.Interpreter
 import Wire.AuthenticationSubsystem
 import Wire.AuthenticationSubsystem.Config
 import Wire.AuthenticationSubsystem.Interpreter
+import Wire.BackgroundJobsPublisher (BackgroundJobsPublisher)
+import Wire.BackgroundJobsPublisher.RabbitMQ (interpretBackgroundJobsPublisherRabbitMQOptional)
 import Wire.BlockListStore
 import Wire.BlockListStore.Cassandra
 import Wire.DeleteQueue
@@ -153,6 +155,7 @@ type BrigLowerLevelEffects =
      DeleteQueue,
      Wire.Events.Events,
      NotificationSubsystem,
+     BackgroundJobsPublisher,
      RateLimit,
      UserGroupStore,
      Error AppSubsystemError,
@@ -363,6 +366,7 @@ runBrigToIO e (AppT ma) = do
               . mapError appSubsystemErrorToHttpError
               . interpretUserGroupStoreToPostgres
               . interpretRateLimit e.rateLimitEnv
+              . interpretBackgroundJobsPublisherRabbitMQOptional e.requestId e.amqpJobsPublisherChannel
               . runNotificationSubsystemGundeck (defaultNotificationSubsystemConfig e.requestId)
               . runEvents
               . runDeleteQueue e.internalEvents
diff --git a/services/galley/galley.cabal b/services/galley/galley.cabal
index 727c8b4d7c..38356fc134 100644
--- a/services/galley/galley.cabal
+++ b/services/galley/galley.cabal
@@ -78,7 +78,6 @@ library
     Galley.API.Action.Leave
     Galley.API.Action.Notify
     Galley.API.Action.Reset
-    Galley.API.Cells
     Galley.API.Clients
     Galley.API.Create
     Galley.API.CustomBackend
@@ -144,7 +143,6 @@ library
     Galley.Cassandra.Proposal
     Galley.Cassandra.Queries
     Galley.Cassandra.SearchVisibility
-    Galley.Cassandra.Services
     Galley.Cassandra.Store
     Galley.Cassandra.Team
     Galley.Cassandra.TeamFeatures
@@ -154,28 +152,22 @@ library
     Galley.Data.TeamNotifications
     Galley.Data.Types
     Galley.Effects
-    Galley.Effects.BackendNotificationQueueAccess
     Galley.Effects.ClientStore
     Galley.Effects.CodeStore
     Galley.Effects.CustomBackendStore
-    Galley.Effects.ExternalAccess
     Galley.Effects.FederatorAccess
-    Galley.Effects.FireAndForget
     Galley.Effects.LegalHoldStore
     Galley.Effects.ProposalStore
     Galley.Effects.Queue
     Galley.Effects.SearchVisibilityStore
-    Galley.Effects.ServiceStore
     Galley.Effects.SparAccess
     Galley.Effects.TeamFeatureStore
     Galley.Effects.TeamMemberStore
     Galley.Effects.TeamNotificationStore
     Galley.Effects.TeamStore
     Galley.Env
-    Galley.External
     Galley.External.LegalHoldService
     Galley.External.LegalHoldService.Internal
-    Galley.Intra.BackendNotificationQueue
     Galley.Intra.Effects
     Galley.Intra.Federator
     Galley.Intra.Journal
diff --git a/services/galley/src/Galley/API/Action.hs b/services/galley/src/Galley/API/Action.hs
index 83d543d5d1..3581a5262e 100644
--- a/services/galley/src/Galley/API/Action.hs
+++ b/services/galley/src/Galley/API/Action.hs
@@ -33,7 +33,7 @@ module Galley.API.Action
 
     -- * Utilities
     addMembersToLocalConversation,
-    notifyConversationAction,
+    sendConversationActionNotifications,
     updateLocalStateOfRemoteConv,
     addLocalUsersToRemoteConv,
     ConversationUpdate,
@@ -45,6 +45,8 @@ module Galley.API.Action
   )
 where
 
+--
+
 import Control.Arrow ((&&&))
 import Control.Error (headMay)
 import Control.Lens
@@ -79,7 +81,6 @@ import Galley.Data.Scope (Scope (ReusableCode))
 import Galley.Effects
 import Galley.Effects.CodeStore qualified as E
 import Galley.Effects.FederatorAccess qualified as E
-import Galley.Effects.FireAndForget qualified as E
 import Galley.Effects.ProposalStore qualified as E
 import Galley.Effects.TeamStore qualified as E
 import Galley.Env (Env)
@@ -120,6 +121,8 @@ import Wire.API.Team.Permission (Perm (AddRemoveConvMember, ModifyConvName))
 import Wire.API.User as User
 import Wire.BrigAPIAccess qualified as E
 import Wire.ConversationStore qualified as E
+import Wire.ConversationSubsystem
+import Wire.FireAndForget qualified as E
 import Wire.NotificationSubsystem
 import Wire.Sem.Now (Now)
 import Wire.Sem.Now qualified as Now
@@ -496,6 +499,7 @@ performAction ::
     Member BackendNotificationQueueAccess r,
     Member TeamCollaboratorsSubsystem r,
     Member (Error FederationError) r,
+    Member ConversationSubsystem r,
     Member E.MLSCommitLockStore r
   ) =>
   Sing tag ->
@@ -612,6 +616,7 @@ performConversationJoin ::
   forall r.
   ( HasConversationActionEffects 'ConversationJoinTag r,
     Member BackendNotificationQueueAccess r,
+    Member ConversationSubsystem r,
     Member TeamCollaboratorsSubsystem r
   ) =>
   Qualified UserId ->
@@ -756,7 +761,8 @@ performConversationJoin qusr lconv (ConversationJoin invited role joinType) = do
 performConversationAccessData ::
   ( HasConversationActionEffects 'ConversationAccessDataTag r,
     Member (Error FederationError) r,
-    Member BackendNotificationQueueAccess r
+    Member BackendNotificationQueueAccess r,
+    Member ConversationSubsystem r
   ) =>
   Qualified UserId ->
   Local StoredConversation ->
@@ -842,9 +848,7 @@ updateLocalConversation ::
     Member (ErrorS ('ActionDenied (ConversationActionPermission tag))) r,
     Member (ErrorS 'InvalidOperation) r,
     Member (ErrorS 'ConvNotFound) r,
-    Member ExternalAccess r,
-    Member NotificationSubsystem r,
-    Member Now r,
+    Member ConversationSubsystem r,
     HasConversationActionEffects tag r,
     SingI tag,
     Member TeamStore r,
@@ -880,9 +884,7 @@ updateLocalConversationUnchecked ::
     Member (ErrorS ('ActionDenied (ConversationActionPermission tag))) r,
     Member (ErrorS 'ConvNotFound) r,
     Member (ErrorS 'InvalidOperation) r,
-    Member ExternalAccess r,
-    Member NotificationSubsystem r,
-    Member Now r,
+    Member ConversationSubsystem r,
     HasConversationActionEffects tag r,
     Member TeamStore r,
     Member TeamCollaboratorsSubsystem r,
@@ -899,7 +901,7 @@ updateLocalConversationUnchecked lconv qusr con action = do
   mTeamMember <- foldQualified lconv (getTeamMembership conv) (const $ pure Nothing) qusr
   ensureConversationActionAllowed (sing @tag) lcnv conv mTeamMember
   par <- performAction (sing @tag) qusr lconv action
-  notifyConversationAction
+  sendConversationActionNotifications
     (sing @tag)
     qusr
     False
diff --git a/services/galley/src/Galley/API/Action/Kick.hs b/services/galley/src/Galley/API/Action/Kick.hs
index b6d22c6dda..af1820dd67 100644
--- a/services/galley/src/Galley/API/Action/Kick.hs
+++ b/services/galley/src/Galley/API/Action/Kick.hs
@@ -18,6 +18,7 @@ import Wire.API.Conversation hiding (Conversation, Member)
 import Wire.API.Conversation.Action
 import Wire.API.Event.LeaveReason
 import Wire.API.Federation.Error
+import Wire.ConversationSubsystem
 import Wire.NotificationSubsystem
 import Wire.Sem.Now (Now)
 import Wire.StoredConversation
@@ -31,6 +32,7 @@ kickMember ::
   ( Member BackendNotificationQueueAccess r,
     Member (Error FederationError) r,
     Member ExternalAccess r,
+    Member ConversationSubsystem r,
     Member NotificationSubsystem r,
     Member ProposalStore r,
     Member Now r,
@@ -46,7 +48,7 @@ kickMember ::
   Sem r ()
 kickMember qusr lconv targets victim = void . runError @NoChanges $ do
   leaveConversation victim lconv
-  notifyConversationAction
+  sendConversationActionNotifications
     (sing @'ConversationRemoveMembersTag)
     qusr
     True
diff --git a/services/galley/src/Galley/API/Action/Notify.hs b/services/galley/src/Galley/API/Action/Notify.hs
index 2c01c1c6b2..5bfaff6376 100644
--- a/services/galley/src/Galley/API/Action/Notify.hs
+++ b/services/galley/src/Galley/API/Action/Notify.hs
@@ -5,35 +5,17 @@ import Data.Qualified
 import Data.Singletons
 import Galley.API.Util
 import Galley.Effects
-import Galley.Effects.BackendNotificationQueueAccess
 import Imports hiding ((\\))
-import Network.AMQP qualified as Q
 import Polysemy
-import Polysemy.Error
 import Wire.API.Conversation hiding (Conversation, Member)
 import Wire.API.Conversation.Action
-import Wire.API.Event.Conversation
-import Wire.API.Federation.API
-import Wire.API.Federation.API.Galley
-import Wire.API.Federation.Error
+import Wire.ConversationSubsystem
 import Wire.NotificationSubsystem
-import Wire.Sem.Now (Now)
-import Wire.Sem.Now qualified as Now
 import Wire.StoredConversation
 
-data LocalConversationUpdate = LocalConversationUpdate
-  { lcuEvent :: Event,
-    lcuUpdate :: ConversationUpdate
-  }
-  deriving (Show)
-
-notifyConversationAction ::
+sendConversationActionNotifications ::
   forall tag r.
-  ( Member BackendNotificationQueueAccess r,
-    Member ExternalAccess r,
-    Member (Error FederationError) r,
-    Member NotificationSubsystem r,
-    Member Now r
+  ( Member ConversationSubsystem r
   ) =>
   Sing tag ->
   Qualified UserId ->
@@ -44,38 +26,15 @@ notifyConversationAction ::
   ConversationAction (tag :: ConversationActionTag) ->
   ExtraConversationData ->
   Sem r LocalConversationUpdate
-notifyConversationAction tag quid notifyOrigDomain con lconv targets action extraData = do
-  now <- Now.get
-  let lcnv = fmap (.id_) lconv
-      conv = tUnqualified lconv
-      tid = conv.metadata.cnvmTeam
-      e = conversationActionToEvent tag now quid (tUntagged lcnv) extraData Nothing tid action
-      mkUpdate uids =
-        ConversationUpdate
-          { time = now,
-            origUserId = quid,
-            convId = tUnqualified lcnv,
-            alreadyPresentUsers = uids,
-            action = SomeConversationAction tag action,
-            extraConversationData = Just extraData
-          }
-  update <-
-    fmap (fromMaybe (mkUpdate []) . asum . map tUnqualified) $
-      enqueueNotificationsConcurrently Q.Persistent (toList (bmRemotes targets)) $
-        \ruids -> do
-          let update = mkUpdate (tUnqualified ruids)
-          -- if notifyOrigDomain is false, filter out user from quid's domain,
-          -- because quid's backend will update local state and notify its users
-          -- itself using the ConversationUpdate returned by this function
-          if notifyOrigDomain || tDomain ruids /= qDomain quid
-            then do
-              makeConversationUpdateBundle update >>= sendBundle
-              pure Nothing
-            else pure (Just update)
-
-  -- notify local participants and bots
-  pushConversationEvent con conv e (qualifyAs lcnv (bmLocals targets)) (bmBots targets)
-
-  -- return both the event and the 'ConversationUpdate' structure corresponding
-  -- to the originating domain (if it is remote)
-  pure $ LocalConversationUpdate e update
+sendConversationActionNotifications tag quid notifyOrigDomain con lconv targets action extraData = do
+  notifyConversationAction
+    tag
+    quid
+    notifyOrigDomain
+    con
+    lconv
+    (bmLocals targets)
+    (bmRemotes targets)
+    (bmBots targets)
+    action
+    extraData
diff --git a/services/galley/src/Galley/API/Action/Reset.hs b/services/galley/src/Galley/API/Action/Reset.hs
index 4823ad27d0..b7c14126d1 100644
--- a/services/galley/src/Galley/API/Action/Reset.hs
+++ b/services/galley/src/Galley/API/Action/Reset.hs
@@ -31,6 +31,7 @@ import Wire.API.MLS.SubConversation
 import Wire.API.Routes.Public.Galley.MLS
 import Wire.API.VersionInfo
 import Wire.ConversationStore
+import Wire.ConversationSubsystem
 import Wire.NotificationSubsystem
 import Wire.Sem.Now (Now)
 import Wire.StoredConversation as Data
@@ -44,6 +45,7 @@ resetLocalMLSMainConversation ::
     Member BackendNotificationQueueAccess r,
     Member FederatorAccess r,
     Member ExternalAccess r,
+    Member ConversationSubsystem r,
     Member NotificationSubsystem r,
     Member ProposalStore r,
     Member Random r,
diff --git a/services/galley/src/Galley/API/Cells.hs b/services/galley/src/Galley/API/Cells.hs
deleted file mode 100644
index 38c16811b8..0000000000
--- a/services/galley/src/Galley/API/Cells.hs
+++ /dev/null
@@ -1,55 +0,0 @@
--- This file is part of the Wire Server implementation.
---
--- Copyright (C) 2025 Wire Swiss GmbH <opensource@wire.com>
---
--- This program is free software: you can redistribute it and/or modify it under
--- the terms of the GNU Affero General Public License as published by the Free
--- Software Foundation, either version 3 of the License, or (at your option) any
--- later version.
---
--- This program is distributed in the hope that it will be useful, but WITHOUT
--- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
--- FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
--- details.
---
--- You should have received a copy of the GNU Affero General Public License along
--- with this program. If not, see <https://www.gnu.org/licenses/>.
-
-module Galley.API.Cells
-  ( HasCellsState (..),
-    shouldPushToCells,
-  )
-where
-
-import Data.Default
-import Imports
-import Wire.API.Conversation
-import Wire.API.Conversation qualified as Public
-import Wire.API.Conversation.CellsState
-import Wire.API.Event.Conversation
-import Wire.StoredConversation
-
-class HasCellsState a where
-  getCellsState :: a -> CellsState
-
-instance HasCellsState CellsState where
-  getCellsState = id
-
-instance HasCellsState StoredConversation where
-  getCellsState = getCellsState . (.metadata)
-
-instance HasCellsState Public.OwnConversation where
-  getCellsState = getCellsState . Public.cnvMetadata
-
-instance HasCellsState ConversationMetadata where
-  getCellsState = cnvmCellsState
-
-instance HasCellsState () where
-  getCellsState = def
-
-shouldPushToCells :: (HasCellsState a) => a -> Event -> Bool
-shouldPushToCells st e =
-  isCellsConversationEvent (evtType e) && case getCellsState st of
-    CellsDisabled -> False
-    CellsPending -> True
-    CellsReady -> True
diff --git a/services/galley/src/Galley/API/Clients.hs b/services/galley/src/Galley/API/Clients.hs
index b409b9049b..1fda288d62 100644
--- a/services/galley/src/Galley/API/Clients.hs
+++ b/services/galley/src/Galley/API/Clients.hs
@@ -30,7 +30,6 @@ import Galley.API.MLS.Removal
 import Galley.API.Query qualified as Query
 import Galley.API.Util
 import Galley.Effects
-import Galley.Effects.BackendNotificationQueueAccess
 import Galley.Effects.ClientStore qualified as E
 import Galley.Env
 import Galley.Types.Clients (clientIds)
@@ -46,6 +45,7 @@ import Wire.API.Federation.API
 import Wire.API.Federation.API.Galley
 import Wire.API.Federation.Error
 import Wire.API.Routes.MultiTablePaging
+import Wire.BackendNotificationQueueAccess
 import Wire.ConversationStore (getConversation)
 import Wire.NotificationSubsystem
 import Wire.Sem.Now (Now)
diff --git a/services/galley/src/Galley/API/Create.hs b/services/galley/src/Galley/API/Create.hs
index ba40896ba8..3336979830 100644
--- a/services/galley/src/Galley/API/Create.hs
+++ b/services/galley/src/Galley/API/Create.hs
@@ -43,7 +43,6 @@ import Data.Range
 import Data.Set qualified as Set
 import Data.UUID.Tagged qualified as U
 import Galley.API.Action
-import Galley.API.Cells
 import Galley.API.Error
 import Galley.API.MLS
 import Galley.API.Mapping
diff --git a/services/galley/src/Galley/API/Federation.hs b/services/galley/src/Galley/API/Federation.hs
index 2cbb40b6f7..0c98f4a751 100644
--- a/services/galley/src/Galley/API/Federation.hs
+++ b/services/galley/src/Galley/API/Federation.hs
@@ -55,7 +55,6 @@ import Galley.API.Push
 import Galley.API.Util
 import Galley.App
 import Galley.Effects
-import Galley.Effects.FireAndForget qualified as E
 import Galley.Options
 import Galley.Types.Conversations.One2One
 import Imports
@@ -94,6 +93,8 @@ import Wire.API.Routes.Public.Galley.MLS
 import Wire.API.ServantProto
 import Wire.API.User (BaseProtocolTag (..))
 import Wire.ConversationStore qualified as E
+import Wire.ConversationSubsystem
+import Wire.FireAndForget qualified as E
 import Wire.NotificationSubsystem
 import Wire.Sem.Now (Now)
 import Wire.Sem.Now qualified as Now
@@ -267,6 +268,7 @@ leaveConversation ::
     Member (Error InternalError) r,
     Member ExternalAccess r,
     Member FederatorAccess r,
+    Member ConversationSubsystem r,
     Member NotificationSubsystem r,
     Member (Input Env) r,
     Member (Input (Local ())) r,
@@ -316,7 +318,7 @@ leaveConversation requestingDomain lc = do
       do
         outcome <-
           runError @FederationError $
-            notifyConversationAction
+            sendConversationActionNotifications
               SConversationLeaveTag
               leaver
               False
@@ -418,6 +420,7 @@ onUserDeleted ::
     Member FireAndForget r,
     Member (Error FederationError) r,
     Member ExternalAccess r,
+    Member ConversationSubsystem r,
     Member NotificationSubsystem r,
     Member (Input (Local ())) r,
     Member Now r,
@@ -455,7 +458,7 @@ onUserDeleted origDomain udcn = do
               removeUser (qualifyAs lc conv) RemoveUserIncludeMain (tUntagged deletedUser)
               outcome <-
                 runError @FederationError $
-                  notifyConversationAction
+                  sendConversationActionNotifications
                     (sing @'ConversationLeaveTag)
                     untaggedDeletedUser
                     False
@@ -480,6 +483,7 @@ updateConversation ::
     Member ExternalAccess r,
     Member FederatorAccess r,
     Member (Error InternalError) r,
+    Member ConversationSubsystem r,
     Member NotificationSubsystem r,
     Member (Input Env) r,
     Member (Input Opts) r,
@@ -614,6 +618,7 @@ sendMLSCommitBundle ::
     Member (Error FederationError) r,
     Member (Error InternalError) r,
     Member FederatorAccess r,
+    Member ConversationSubsystem r,
     Member NotificationSubsystem r,
     Member (Input (Local ())) r,
     Member (Input Env) r,
diff --git a/services/galley/src/Galley/API/Internal.hs b/services/galley/src/Galley/API/Internal.hs
index 95320a676f..ce4aa597d4 100644
--- a/services/galley/src/Galley/API/Internal.hs
+++ b/services/galley/src/Galley/API/Internal.hs
@@ -37,7 +37,6 @@ import Data.Range
 import Data.Singletons
 import Data.Time
 import Galley.API.Action
-import Galley.API.Cells
 import Galley.API.Clients qualified as Clients
 import Galley.API.Create qualified as Create
 import Galley.API.Error
@@ -55,11 +54,9 @@ import Galley.API.Update qualified as Update
 import Galley.API.Util
 import Galley.App
 import Galley.Effects
-import Galley.Effects.BackendNotificationQueueAccess
 import Galley.Effects.ClientStore
 import Galley.Effects.CustomBackendStore
 import Galley.Effects.LegalHoldStore as LegalHoldStore
-import Galley.Effects.ServiceStore
 import Galley.Effects.TeamStore
 import Galley.Effects.TeamStore qualified as E
 import Galley.Monad
@@ -93,13 +90,16 @@ import Wire.API.Routes.MultiTablePaging qualified as MTP
 import Wire.API.Team.Feature
 import Wire.API.User (UserIds (cUsers))
 import Wire.API.User.Client
+import Wire.BackendNotificationQueueAccess
 import Wire.ConversationStore
 import Wire.ConversationStore qualified as E
+import Wire.ConversationSubsystem
 import Wire.NotificationSubsystem
 import Wire.Sem.Now (Now)
 import Wire.Sem.Now qualified as Now
 import Wire.Sem.Paging
 import Wire.Sem.Paging.Cassandra
+import Wire.ServiceStore
 import Wire.StoredConversation
 import Wire.StoredConversation qualified as Data
 import Wire.TeamSubsystem qualified as TeamSubsystem
@@ -325,6 +325,7 @@ rmUser ::
     Member (Error InternalError) r,
     Member ExternalAccess r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input Env) r,
     Member (Input Opts) r,
     Member Now r,
diff --git a/services/galley/src/Galley/API/LegalHold.hs b/services/galley/src/Galley/API/LegalHold.hs
index 8de1a0c435..600784f802 100644
--- a/services/galley/src/Galley/API/LegalHold.hs
+++ b/services/galley/src/Galley/API/LegalHold.hs
@@ -50,7 +50,6 @@ import Galley.API.Update (removeMemberFromLocalConv)
 import Galley.API.Util
 import Galley.App
 import Galley.Effects
-import Galley.Effects.FireAndForget
 import Galley.Effects.LegalHoldStore qualified as LegalHoldData
 import Galley.Effects.TeamMemberStore
 import Galley.Effects.TeamStore
@@ -79,6 +78,8 @@ import Wire.API.Team.Member
 import Wire.API.User.Client.Prekey
 import Wire.BrigAPIAccess
 import Wire.ConversationStore
+import Wire.ConversationSubsystem
+import Wire.FireAndForget
 import Wire.NotificationSubsystem
 import Wire.Sem.Now (Now)
 import Wire.Sem.Paging
@@ -161,6 +162,7 @@ removeSettingsInternalPaging ::
     Member FederatorAccess r,
     Member FireAndForget r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input Env) r,
     Member (Input (Local ())) r,
     Member Now r,
@@ -206,6 +208,7 @@ removeSettings ::
     Member FederatorAccess r,
     Member FireAndForget r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input Env) r,
     Member (Input (Local ())) r,
     Member Now r,
@@ -259,6 +262,7 @@ removeSettings' ::
     Member FederatorAccess r,
     Member FireAndForget r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member Now r,
     Member (Input (Local ())) r,
     Member (Input Env) r,
@@ -310,6 +314,7 @@ grantConsent ::
     Member ExternalAccess r,
     Member FederatorAccess r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input Env) r,
     Member Now r,
     Member LegalHoldStore r,
@@ -357,6 +362,7 @@ requestDevice ::
     Member ExternalAccess r,
     Member FederatorAccess r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input (Local ())) r,
     Member (Input Env) r,
     Member Now r,
@@ -450,6 +456,7 @@ approveDevice ::
     Member ExternalAccess r,
     Member FederatorAccess r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input (Local ())) r,
     Member (Input Env) r,
     Member Now r,
@@ -527,6 +534,7 @@ disableForUser ::
     Member ExternalAccess r,
     Member FederatorAccess r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input Env) r,
     Member (Input (Local ())) r,
     Member Now r,
@@ -592,6 +600,7 @@ changeLegalholdStatusAndHandlePolicyConflicts ::
     Member ExternalAccess r,
     Member FederatorAccess r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input Env) r,
     Member Now r,
     Member LegalHoldStore r,
@@ -708,6 +717,7 @@ handleGroupConvPolicyConflicts ::
     Member ExternalAccess r,
     Member FederatorAccess r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input Env) r,
     Member Now r,
     Member ProposalStore r,
diff --git a/services/galley/src/Galley/API/MLS/Commit/InternalCommit.hs b/services/galley/src/Galley/API/MLS/Commit/InternalCommit.hs
index 602f3766a5..9965e3c5c9 100644
--- a/services/galley/src/Galley/API/MLS/Commit/InternalCommit.hs
+++ b/services/galley/src/Galley/API/MLS/Commit/InternalCommit.hs
@@ -61,6 +61,7 @@ import Wire.API.Unreachable
 import Wire.API.User.Client
 import Wire.ConversationStore
 import Wire.ConversationStore.MLS.Types
+import Wire.ConversationSubsystem
 import Wire.StoredConversation
 
 processInternalCommit ::
@@ -73,6 +74,7 @@ processInternalCommit ::
     Member (ErrorS 'MLSIdentityMismatch) r,
     Member (ErrorS 'MissingLegalholdConsent) r,
     Member (ErrorS 'GroupIdVersionNotSupported) r,
+    Member ConversationSubsystem r,
     Member Resource r,
     Member Random r,
     Member (ErrorS MLSInvalidLeafNodeSignature) r,
@@ -255,7 +257,7 @@ processInternalCommit senderIdentity con lConvOrSub ciphersuite ciphersuiteUpdat
                       )
                       $ nonEmpty (bmQualifiedMembers lconv bm)
                   update <-
-                    notifyConversationAction
+                    sendConversationActionNotifications
                       SConversationJoinTag
                       senderUser
                       False
@@ -329,7 +331,7 @@ mkClientData clientInfo =
     }
 
 addMembers ::
-  (HasProposalActionEffects r, Member MLSCommitLockStore r) =>
+  (HasProposalActionEffects r, Member ConversationSubsystem r, Member MLSCommitLockStore r) =>
   Qualified UserId ->
   Maybe ConnId ->
   Local ConvOrSubConv ->
@@ -353,7 +355,7 @@ addMembers qusr con lConvOrSub users = case tUnqualified lConvOrSub of
   SubConv _ _ -> pure []
 
 removeMembers ::
-  (HasProposalActionEffects r, Member MLSCommitLockStore r) =>
+  (HasProposalActionEffects r, Member ConversationSubsystem r, Member MLSCommitLockStore r) =>
   Qualified UserId ->
   Maybe ConnId ->
   Local ConvOrSubConv ->
diff --git a/services/galley/src/Galley/API/MLS/Message.hs b/services/galley/src/Galley/API/MLS/Message.hs
index 2ee59d49b3..c317a4f8c2 100644
--- a/services/galley/src/Galley/API/MLS/Message.hs
+++ b/services/galley/src/Galley/API/MLS/Message.hs
@@ -84,6 +84,7 @@ import Wire.API.MLS.SubConversation
 import Wire.API.Team.LegalHold
 import Wire.ConversationStore
 import Wire.ConversationStore.MLS.Types
+import Wire.ConversationSubsystem
 import Wire.NotificationSubsystem
 import Wire.Sem.Now qualified as Now
 import Wire.StoredConversation
@@ -165,6 +166,7 @@ postMLSCommitBundle ::
     Member Resource r,
     Members MLSBundleStaticErrors r,
     HasProposalEffects r,
+    Member ConversationSubsystem r,
     Member MLSCommitLockStore r
   ) =>
   Local x ->
@@ -192,6 +194,7 @@ postMLSCommitBundleFromLocalUser ::
     Member Resource r,
     Members MLSBundleStaticErrors r,
     HasProposalEffects r,
+    Member ConversationSubsystem r,
     Member MLSCommitLockStore r
   ) =>
   Local UserId ->
@@ -219,6 +222,7 @@ postMLSCommitBundleToLocalConv ::
     Member Resource r,
     Members MLSBundleStaticErrors r,
     HasProposalEffects r,
+    Member ConversationSubsystem r,
     Member MLSCommitLockStore r
   ) =>
   Qualified UserId ->
diff --git a/services/galley/src/Galley/API/MLS/Propagate.hs b/services/galley/src/Galley/API/MLS/Propagate.hs
index 4300af2de3..40242f6566 100644
--- a/services/galley/src/Galley/API/MLS/Propagate.hs
+++ b/services/galley/src/Galley/API/MLS/Propagate.hs
@@ -26,7 +26,6 @@ import Data.Map qualified as Map
 import Data.Qualified
 import Galley.API.Push
 import Galley.Effects
-import Galley.Effects.BackendNotificationQueueAccess
 import Imports
 import Network.AMQP qualified as Q
 import Polysemy
@@ -43,6 +42,7 @@ import Wire.API.MLS.Serialisation
 import Wire.API.MLS.SubConversation
 import Wire.API.Message
 import Wire.API.Push.V2 (RecipientClients (..))
+import Wire.BackendNotificationQueueAccess
 import Wire.ConversationStore.MLS.Types
 import Wire.NotificationSubsystem
 import Wire.Sem.Now (Now)
diff --git a/services/galley/src/Galley/API/MLS/Reset.hs b/services/galley/src/Galley/API/MLS/Reset.hs
index f5cfe82934..a1b2addba7 100644
--- a/services/galley/src/Galley/API/MLS/Reset.hs
+++ b/services/galley/src/Galley/API/MLS/Reset.hs
@@ -39,6 +39,7 @@ import Wire.API.Federation.Error
 import Wire.API.MLS.SubConversation
 import Wire.API.Routes.Public.Galley.MLS
 import Wire.ConversationStore
+import Wire.ConversationSubsystem
 import Wire.NotificationSubsystem
 import Wire.Sem.Now (Now)
 import Wire.TeamCollaboratorsSubsystem
@@ -63,6 +64,7 @@ resetMLSConversation ::
     Member (Error FederationError) r,
     Member BrigAPIAccess r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member ProposalStore r,
     Member Random r,
     Member Resource r,
diff --git a/services/galley/src/Galley/API/MLS/Welcome.hs b/services/galley/src/Galley/API/MLS/Welcome.hs
index 06dac306d3..b6c9f4b5fa 100644
--- a/services/galley/src/Galley/API/MLS/Welcome.hs
+++ b/services/galley/src/Galley/API/MLS/Welcome.hs
@@ -31,7 +31,6 @@ import Data.Map qualified as Map
 import Data.Qualified
 import Data.Time
 import Galley.API.Push
-import Galley.Effects.ExternalAccess
 import Galley.Effects.FederatorAccess
 import Imports
 import Network.Wai.Utilities.JSONResponse
@@ -51,6 +50,7 @@ import Wire.API.MLS.SubConversation
 import Wire.API.MLS.Welcome
 import Wire.API.Message
 import Wire.API.Push.V2 (RecipientClients (..))
+import Wire.ExternalAccess
 import Wire.NotificationSubsystem
 import Wire.Sem.Now (Now)
 import Wire.Sem.Now qualified as Now
diff --git a/services/galley/src/Galley/API/Message.hs b/services/galley/src/Galley/API/Message.hs
index 35ea6ecb97..87093c07d6 100644
--- a/services/galley/src/Galley/API/Message.hs
+++ b/services/galley/src/Galley/API/Message.hs
@@ -53,7 +53,6 @@ import Galley.API.LegalHold.Conflicts
 import Galley.API.Push
 import Galley.API.Util
 import Galley.Effects
-import Galley.Effects.BackendNotificationQueueAccess
 import Galley.Effects.ClientStore
 import Galley.Effects.FederatorAccess
 import Galley.Effects.TeamStore
@@ -81,6 +80,7 @@ import Wire.API.Team.LegalHold
 import Wire.API.Team.Member
 import Wire.API.User.Client
 import Wire.API.UserMap (UserMap (..))
+import Wire.BackendNotificationQueueAccess
 import Wire.BrigAPIAccess
 import Wire.ConversationStore
 import Wire.NotificationSubsystem (NotificationSubsystem)
diff --git a/services/galley/src/Galley/API/Push.hs b/services/galley/src/Galley/API/Push.hs
index d9d5da6522..2fe2abc6d5 100644
--- a/services/galley/src/Galley/API/Push.hs
+++ b/services/galley/src/Galley/API/Push.hs
@@ -35,7 +35,6 @@ import Data.Json.Util
 import Data.List1 qualified as List1
 import Data.Map qualified as Map
 import Data.Qualified
-import Galley.Effects.ExternalAccess
 import Imports
 import Polysemy
 import Polysemy.TinyLog
@@ -43,6 +42,7 @@ import System.Logger.Class qualified as Log
 import Wire.API.Event.Conversation
 import Wire.API.Message
 import Wire.API.Push.V2 (RecipientClients (RecipientClientsSome), Route (..))
+import Wire.ExternalAccess
 import Wire.NotificationSubsystem
 import Wire.StoredConversation
 
diff --git a/services/galley/src/Galley/API/Teams.hs b/services/galley/src/Galley/API/Teams.hs
index ff1513aab1..589f9fc837 100644
--- a/services/galley/src/Galley/API/Teams.hs
+++ b/services/galley/src/Galley/API/Teams.hs
@@ -86,7 +86,6 @@ import Galley.API.Update qualified as API
 import Galley.API.Util
 import Galley.App
 import Galley.Effects
-import Galley.Effects.ExternalAccess qualified as E
 import Galley.Effects.LegalHoldStore qualified as Data
 import Galley.Effects.Queue qualified as E
 import Galley.Effects.SearchVisibilityStore qualified as SearchVisibilityData
@@ -132,6 +131,8 @@ import Wire.API.User qualified as U
 import Wire.BrigAPIAccess qualified as Brig
 import Wire.BrigAPIAccess qualified as E
 import Wire.ConversationStore qualified as E
+import Wire.ConversationSubsystem
+import Wire.ExternalAccess qualified as E
 import Wire.ListItems qualified as E
 import Wire.NotificationSubsystem
 import Wire.Sem.Now
@@ -755,21 +756,19 @@ updateTeamMember lzusr zcon tid newMem = do
         && permissionsRole targetPermissions /= Just RoleOwner
 
 deleteTeamMember ::
-  ( Member BackendNotificationQueueAccess r,
-    Member BrigAPIAccess r,
+  ( Member BrigAPIAccess r,
     Member ConversationStore r,
     Member (Error AuthenticationError) r,
-    Member (Error FederationError) r,
     Member (Error InvalidInput) r,
     Member (ErrorS 'AccessDenied) r,
     Member (ErrorS 'TeamMemberNotFound) r,
     Member (ErrorS 'TeamNotFound) r,
     Member (ErrorS 'NotATeamMember) r,
     Member (ErrorS OperationDenied) r,
-    Member ExternalAccess r,
     Member (Input Opts) r,
     Member Now r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member TeamFeatureStore r,
     Member TeamStore r,
     Member P.TinyLog r
@@ -783,21 +782,19 @@ deleteTeamMember ::
 deleteTeamMember lusr zcon tid remove body = deleteTeamMember' lusr zcon tid remove (Just body)
 
 deleteNonBindingTeamMember ::
-  ( Member BackendNotificationQueueAccess r,
-    Member BrigAPIAccess r,
+  ( Member BrigAPIAccess r,
     Member ConversationStore r,
     Member (Error AuthenticationError) r,
-    Member (Error FederationError) r,
     Member (Error InvalidInput) r,
     Member (ErrorS 'AccessDenied) r,
     Member (ErrorS 'TeamMemberNotFound) r,
     Member (ErrorS 'TeamNotFound) r,
     Member (ErrorS 'NotATeamMember) r,
     Member (ErrorS OperationDenied) r,
-    Member ExternalAccess r,
     Member (Input Opts) r,
     Member Now r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member TeamFeatureStore r,
     Member TeamStore r,
     Member P.TinyLog r
@@ -811,21 +808,19 @@ deleteNonBindingTeamMember lusr zcon tid remove = deleteTeamMember' lusr zcon ti
 
 -- | 'TeamMemberDeleteData' is only required for binding teams
 deleteTeamMember' ::
-  ( Member BackendNotificationQueueAccess r,
-    Member BrigAPIAccess r,
+  ( Member BrigAPIAccess r,
     Member ConversationStore r,
     Member (Error AuthenticationError) r,
     Member (Error InvalidInput) r,
-    Member (Error FederationError) r,
     Member (ErrorS 'AccessDenied) r,
     Member (ErrorS 'TeamMemberNotFound) r,
     Member (ErrorS 'TeamNotFound) r,
     Member (ErrorS 'NotATeamMember) r,
     Member (ErrorS OperationDenied) r,
-    Member ExternalAccess r,
     Member (Input Opts) r,
     Member Now r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member TeamFeatureStore r,
     Member TeamStore r,
     Member P.TinyLog r
@@ -880,11 +875,9 @@ deleteTeamMember' lusr zcon tid remove mBody = do
 -- This function is "unchecked" because it does not validate that the user has the `RemoveTeamMember` permission.
 uncheckedDeleteTeamMember ::
   forall r.
-  ( Member BackendNotificationQueueAccess r,
-    Member ConversationStore r,
+  ( Member ConversationStore r,
     Member NotificationSubsystem r,
-    Member (Error FederationError) r,
-    Member ExternalAccess r,
+    Member ConversationSubsystem r,
     Member Now r,
     Member TeamStore r
   ) =>
@@ -943,12 +936,8 @@ uncheckedDeleteTeamMember lusr zcon tid remove (Right mems) = do
 
 removeFromConvsAndPushConvLeaveEvent ::
   forall r.
-  ( Member BackendNotificationQueueAccess r,
-    Member ConversationStore r,
-    Member (Error FederationError) r,
-    Member ExternalAccess r,
-    Member NotificationSubsystem r,
-    Member Now r
+  ( Member ConversationStore r,
+    Member ConversationSubsystem r
   ) =>
   Local UserId ->
   Maybe ConnId ->
@@ -973,7 +962,7 @@ removeFromConvsAndPushConvLeaveEvent lusr zcon tid remove = do
                       (Set.fromList $ (.id_) <$> dc.remoteMembers)
                       (Set.fromList bots)
               void $
-                notifyConversationAction
+                sendConversationActionNotifications
                   (sing @'ConversationRemoveMembersTag)
                   (tUntagged lusr)
                   True
@@ -1035,9 +1024,7 @@ deleteTeamConversation ::
     Member (ErrorS ('ActionDenied 'Public.DeleteConversation)) r,
     Member FederatorAccess r,
     Member ProposalStore r,
-    Member ExternalAccess r,
-    Member NotificationSubsystem r,
-    Member Now r,
+    Member ConversationSubsystem r,
     Member TeamStore r,
     Member TeamCollaboratorsSubsystem r,
     Member E.MLSCommitLockStore r
@@ -1335,13 +1322,11 @@ checkAdminLimit adminCount =
 -- | Removing a team collaborator and clean their conversations
 removeTeamCollaborator ::
   forall r.
-  ( Member BackendNotificationQueueAccess r,
-    Member ConversationStore r,
-    Member (Error FederationError) r,
+  ( Member ConversationStore r,
     Member (ErrorS OperationDenied) r,
     Member (ErrorS NotATeamMember) r,
-    Member ExternalAccess r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input Opts) r,
     Member Now r,
     Member P.TinyLog r,
diff --git a/services/galley/src/Galley/API/Teams/Features.hs b/services/galley/src/Galley/API/Teams/Features.hs
index e6a7fd9fab..d5f4ff10fd 100644
--- a/services/galley/src/Galley/API/Teams/Features.hs
+++ b/services/galley/src/Galley/API/Teams/Features.hs
@@ -67,6 +67,7 @@ import Wire.API.Team.Feature
 import Wire.API.Team.Member
 import Wire.BrigAPIAccess (updateSearchVisibilityInbound)
 import Wire.ConversationStore (MLSCommitLockStore)
+import Wire.ConversationSubsystem
 import Wire.NotificationSubsystem
 import Wire.Sem.Now (Now)
 import Wire.Sem.Paging
@@ -326,6 +327,7 @@ instance SetFeatureConfig LegalholdConfig where
         Member FederatorAccess r,
         Member FireAndForget r,
         Member NotificationSubsystem r,
+        Member ConversationSubsystem r,
         Member (Input (Local ())) r,
         Member (Input Env) r,
         Member Now r,
diff --git a/services/galley/src/Galley/API/Update.hs b/services/galley/src/Galley/API/Update.hs
index 72830a9ada..b9d8cd7ff0 100644
--- a/services/galley/src/Galley/API/Update.hs
+++ b/services/galley/src/Galley/API/Update.hs
@@ -88,7 +88,6 @@ import Data.Set qualified as Set
 import Data.Singletons
 import Galley.API.Action
 import Galley.API.Action.Kick (kickMember)
-import Galley.API.Cells
 import Galley.API.Error
 import Galley.API.Mapping
 import Galley.API.Message
@@ -100,7 +99,6 @@ import Galley.Data.Types
 import Galley.Effects
 import Galley.Effects.ClientStore qualified as E
 import Galley.Effects.CodeStore qualified as E
-import Galley.Effects.ExternalAccess qualified as E
 import Galley.Effects.FederatorAccess qualified as E
 import Galley.Effects.TeamStore qualified as E
 import Galley.Options
@@ -133,6 +131,8 @@ import Wire.API.Team.Feature
 import Wire.API.Team.Member
 import Wire.API.User.Client
 import Wire.ConversationStore qualified as E
+import Wire.ConversationSubsystem
+import Wire.ExternalAccess qualified as E
 import Wire.HashPassword as HashPassword
 import Wire.NotificationSubsystem
 import Wire.RateLimit
@@ -270,6 +270,7 @@ type UpdateConversationAccessEffects =
      FederatorAccess,
      FireAndForget,
      NotificationSubsystem,
+     ConversationSubsystem,
      Input Env,
      ProposalStore,
      Random,
@@ -325,8 +326,8 @@ updateConversationReceiptMode ::
     Member ExternalAccess r,
     Member FederatorAccess r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input (Local ())) r,
-    Member Now r,
     Member TinyLog r,
     Member TeamStore r,
     Member TeamCollaboratorsSubsystem r,
@@ -406,8 +407,8 @@ updateConversationReceiptModeUnqualified ::
     Member ExternalAccess r,
     Member FederatorAccess r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input (Local ())) r,
-    Member Now r,
     Member TinyLog r,
     Member TeamStore r,
     Member TeamCollaboratorsSubsystem r,
@@ -427,9 +428,7 @@ updateConversationMessageTimer ::
     Member (ErrorS 'ConvNotFound) r,
     Member (ErrorS 'InvalidOperation) r,
     Member (Error FederationError) r,
-    Member ExternalAccess r,
-    Member NotificationSubsystem r,
-    Member Now r,
+    Member ConversationSubsystem r,
     Member TeamStore r,
     Member TeamCollaboratorsSubsystem r,
     Member E.MLSCommitLockStore r
@@ -462,9 +461,7 @@ updateConversationMessageTimerUnqualified ::
     Member (ErrorS 'ConvNotFound) r,
     Member (ErrorS 'InvalidOperation) r,
     Member (Error FederationError) r,
-    Member ExternalAccess r,
-    Member NotificationSubsystem r,
-    Member Now r,
+    Member ConversationSubsystem r,
     Member TeamStore r,
     Member TeamCollaboratorsSubsystem r,
     Member E.MLSCommitLockStore r
@@ -486,11 +483,9 @@ deleteLocalConversation ::
     Member (ErrorS ('ActionDenied 'DeleteConversation)) r,
     Member (ErrorS 'ConvNotFound) r,
     Member (ErrorS 'InvalidOperation) r,
-    Member ExternalAccess r,
     Member FederatorAccess r,
-    Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member ProposalStore r,
-    Member Now r,
     Member TeamStore r,
     Member TeamCollaboratorsSubsystem r,
     Member E.MLSCommitLockStore r
@@ -729,6 +724,7 @@ updateConversationProtocolWithLocalUser ::
     Member ConversationStore r,
     Member TinyLog r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member ExternalAccess r,
     Member FederatorAccess r,
     Member Random r,
@@ -769,7 +765,7 @@ updateChannelAddPermission ::
     Member (Error FederationError) r,
     Member ExternalAccess r,
     Member NotificationSubsystem r,
-    Member Now r,
+    Member ConversationSubsystem r,
     Member TeamStore r,
     Member (Input (Local ())) r,
     Member TinyLog r,
@@ -807,11 +803,9 @@ updateChannelAddPermission lusr zcon qcnv update =
 
 joinConversationByReusableCode ::
   forall r.
-  ( Member BackendNotificationQueueAccess r,
-    Member BrigAPIAccess r,
+  ( Member BrigAPIAccess r,
     Member CodeStore r,
     Member ConversationStore r,
-    Member (Error FederationError) r,
     Member (ErrorS 'CodeNotFound) r,
     Member (ErrorS 'InvalidConversationPassword) r,
     Member (ErrorS 'ConvAccessDenied) r,
@@ -820,10 +814,8 @@ joinConversationByReusableCode ::
     Member (ErrorS 'InvalidOperation) r,
     Member (ErrorS 'NotATeamMember) r,
     Member (ErrorS 'TooManyMembers) r,
-    Member ExternalAccess r,
-    Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input Opts) r,
-    Member Now r,
     Member TeamStore r,
     Member TeamFeatureStore r,
     Member HashPassword r,
@@ -841,19 +833,15 @@ joinConversationByReusableCode lusr zcon req = do
 
 joinConversationById ::
   forall r.
-  ( Member BackendNotificationQueueAccess r,
-    Member BrigAPIAccess r,
+  ( Member BrigAPIAccess r,
     Member ConversationStore r,
-    Member (Error FederationError) r,
     Member (ErrorS 'ConvAccessDenied) r,
     Member (ErrorS 'ConvNotFound) r,
     Member (ErrorS 'InvalidOperation) r,
     Member (ErrorS 'NotATeamMember) r,
     Member (ErrorS 'TooManyMembers) r,
-    Member ExternalAccess r,
-    Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input Opts) r,
-    Member Now r,
     Member TeamStore r
   ) =>
   Local UserId ->
@@ -866,17 +854,13 @@ joinConversationById lusr zcon cnv = do
 
 joinConversation ::
   forall r.
-  ( Member BackendNotificationQueueAccess r,
-    Member BrigAPIAccess r,
-    Member (Error FederationError) r,
+  ( Member BrigAPIAccess r,
     Member (ErrorS 'ConvAccessDenied) r,
     Member (ErrorS 'InvalidOperation) r,
     Member (ErrorS 'NotATeamMember) r,
     Member (ErrorS 'TooManyMembers) r,
-    Member ExternalAccess r,
-    Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input Opts) r,
-    Member Now r,
     Member ConversationStore r,
     Member TeamStore r
   ) =>
@@ -899,7 +883,7 @@ joinConversation lusr zcon conv access = do
     (extraTargets, action) <-
       addMembersToLocalConversation lcnv (UserList users []) roleNameWireMember InternalAdd
     lcuEvent
-      <$> notifyConversationAction
+      <$> sendConversationActionNotifications
         (sing @'ConversationJoinTag)
         (tUntagged lusr)
         False
@@ -930,6 +914,7 @@ addMembers ::
     Member (Error UnreachableBackends) r,
     Member ExternalAccess r,
     Member FederatorAccess r,
+    Member ConversationSubsystem r,
     Member NotificationSubsystem r,
     Member (Input Env) r,
     Member (Input Opts) r,
@@ -984,6 +969,7 @@ addMembersUnqualifiedV2 ::
     Member (Error UnreachableBackends) r,
     Member ExternalAccess r,
     Member FederatorAccess r,
+    Member ConversationSubsystem r,
     Member NotificationSubsystem r,
     Member (Input Env) r,
     Member (Input Opts) r,
@@ -1027,6 +1013,7 @@ addMembersUnqualified ::
     Member (Error UnreachableBackends) r,
     Member ExternalAccess r,
     Member FederatorAccess r,
+    Member ConversationSubsystem r,
     Member NotificationSubsystem r,
     Member (Input Env) r,
     Member (Input Opts) r,
@@ -1119,9 +1106,7 @@ updateOtherMemberLocalConv ::
     Member (ErrorS 'InvalidOperation) r,
     Member (ErrorS 'ConvNotFound) r,
     Member (ErrorS 'ConvMemberNotFound) r,
-    Member ExternalAccess r,
-    Member NotificationSubsystem r,
-    Member Now r,
+    Member ConversationSubsystem r,
     Member TeamStore r,
     Member TeamCollaboratorsSubsystem r,
     Member E.MLSCommitLockStore r
@@ -1147,9 +1132,7 @@ updateOtherMemberUnqualified ::
     Member (ErrorS 'InvalidOperation) r,
     Member (ErrorS 'ConvNotFound) r,
     Member (ErrorS 'ConvMemberNotFound) r,
-    Member ExternalAccess r,
-    Member NotificationSubsystem r,
-    Member Now r,
+    Member ConversationSubsystem r,
     Member TeamStore r,
     Member TeamCollaboratorsSubsystem r,
     Member E.MLSCommitLockStore r
@@ -1174,9 +1157,7 @@ updateOtherMember ::
     Member (ErrorS 'InvalidOperation) r,
     Member (ErrorS 'ConvNotFound) r,
     Member (ErrorS 'ConvMemberNotFound) r,
-    Member ExternalAccess r,
-    Member NotificationSubsystem r,
-    Member Now r,
+    Member ConversationSubsystem r,
     Member TeamStore r,
     Member TeamCollaboratorsSubsystem r,
     Member E.MLSCommitLockStore r
@@ -1212,6 +1193,7 @@ removeMemberUnqualified ::
     Member ExternalAccess r,
     Member FederatorAccess r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input Env) r,
     Member Now r,
     Member ProposalStore r,
@@ -1242,6 +1224,7 @@ removeMemberQualified ::
     Member ExternalAccess r,
     Member FederatorAccess r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input Env) r,
     Member Now r,
     Member ProposalStore r,
@@ -1319,6 +1302,7 @@ removeMemberFromLocalConv ::
     Member ExternalAccess r,
     Member FederatorAccess r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Input Env) r,
     Member Now r,
     Member ProposalStore r,
@@ -1365,6 +1349,7 @@ removeMemberFromChannel ::
     Member ExternalAccess r,
     Member FederatorAccess r,
     Member NotificationSubsystem r,
+    Member ConversationSubsystem r,
     Member (Error InternalError) r,
     Member Random r,
     Member TinyLog r,
@@ -1553,9 +1538,7 @@ updateConversationName ::
     Member (ErrorS ('ActionDenied 'ModifyConversationName)) r,
     Member (ErrorS 'ConvNotFound) r,
     Member (ErrorS 'InvalidOperation) r,
-    Member ExternalAccess r,
-    Member NotificationSubsystem r,
-    Member Now r,
+    Member ConversationSubsystem r,
     Member TeamStore r,
     Member TeamCollaboratorsSubsystem r,
     Member E.MLSCommitLockStore r
@@ -1581,9 +1564,7 @@ updateUnqualifiedConversationName ::
     Member (ErrorS ('ActionDenied 'ModifyConversationName)) r,
     Member (ErrorS 'ConvNotFound) r,
     Member (ErrorS 'InvalidOperation) r,
-    Member ExternalAccess r,
-    Member NotificationSubsystem r,
-    Member Now r,
+    Member ConversationSubsystem r,
     Member TeamStore r,
     Member TeamCollaboratorsSubsystem r,
     Member E.MLSCommitLockStore r
@@ -1605,9 +1586,7 @@ updateLocalConversationName ::
     Member (ErrorS ('ActionDenied 'ModifyConversationName)) r,
     Member (ErrorS 'ConvNotFound) r,
     Member (ErrorS 'InvalidOperation) r,
-    Member ExternalAccess r,
-    Member NotificationSubsystem r,
-    Member Now r,
+    Member ConversationSubsystem r,
     Member TeamStore r,
     Member TeamCollaboratorsSubsystem r,
     Member E.MLSCommitLockStore r
diff --git a/services/galley/src/Galley/API/Util.hs b/services/galley/src/Galley/API/Util.hs
index 545ac8a6a6..9529100c3b 100644
--- a/services/galley/src/Galley/API/Util.hs
+++ b/services/galley/src/Galley/API/Util.hs
@@ -40,15 +40,12 @@ import Data.Set qualified as Set
 import Data.Singletons
 import Data.Text qualified as T
 import Data.Time
-import Galley.API.Cells
 import Galley.API.Error
 import Galley.API.Mapping
 import Galley.Data.Types qualified as DataTypes
 import Galley.Effects
-import Galley.Effects.BackendNotificationQueueAccess
 import Galley.Effects.ClientStore
 import Galley.Effects.CodeStore
-import Galley.Effects.ExternalAccess
 import Galley.Effects.FederatorAccess
 import Galley.Effects.LegalHoldStore
 import Galley.Effects.TeamStore
@@ -67,6 +64,7 @@ import Wire.API.Connection
 import Wire.API.Conversation hiding (Member, cnvAccess, cnvAccessRoles, cnvName, cnvType)
 import Wire.API.Conversation qualified as Public
 import Wire.API.Conversation.Action
+import Wire.API.Conversation.CellsState (HasCellsState)
 import Wire.API.Conversation.Protocol
 import Wire.API.Conversation.Role
 import Wire.API.Error
@@ -90,8 +88,10 @@ import Wire.API.Team.Role
 import Wire.API.User hiding (userId)
 import Wire.API.User.Auth.ReAuth
 import Wire.API.VersionInfo
+import Wire.BackendNotificationQueueAccess
 import Wire.BrigAPIAccess
 import Wire.ConversationStore
+import Wire.ExternalAccess
 import Wire.HashPassword (HashPassword)
 import Wire.HashPassword qualified as HashPassword
 import Wire.NotificationSubsystem
diff --git a/services/galley/src/Galley/App.hs b/services/galley/src/Galley/App.hs
index 09a5cfbf76..d6c4ee7007 100644
--- a/services/galley/src/Galley/App.hs
+++ b/services/galley/src/Galley/App.hs
@@ -32,7 +32,6 @@ module Galley.App
     extEnv,
     aEnv,
     ExtEnv (..),
-    extGetManager,
 
     -- * Running Galley effects
     GalleyEffects,
@@ -61,15 +60,11 @@ import Galley.Cassandra.CustomBackend
 import Galley.Cassandra.LegalHold
 import Galley.Cassandra.Proposal
 import Galley.Cassandra.SearchVisibility
-import Galley.Cassandra.Services
 import Galley.Cassandra.Team
 import Galley.Cassandra.TeamFeatures
 import Galley.Cassandra.TeamNotifications
 import Galley.Effects
-import Galley.Effects.FireAndForget
 import Galley.Env
-import Galley.External
-import Galley.Intra.BackendNotificationQueue
 import Galley.Intra.Effects
 import Galley.Intra.Federator
 import Galley.Keys
@@ -108,10 +103,14 @@ import Wire.API.Error
 import Wire.API.Federation.Error
 import Wire.API.Team.Collaborator
 import Wire.API.Team.Feature
+import Wire.BackendNotificationQueueAccess.RabbitMq qualified as BackendNotificationQueueAccess
 import Wire.BrigAPIAccess.Rpc
 import Wire.ConversationStore.Cassandra
 import Wire.ConversationStore.Postgres
+import Wire.ConversationSubsystem.Interpreter (interpretConversationSubsystem)
 import Wire.Error
+import Wire.ExternalAccess.External
+import Wire.FireAndForget
 import Wire.GundeckAPIAccess (runGundeckAPIAccess)
 import Wire.HashPassword.Interpreter
 import Wire.NotificationSubsystem.Interpreter (runNotificationSubsystemGundeck)
@@ -122,6 +121,7 @@ import Wire.Rpc
 import Wire.Sem.Delay
 import Wire.Sem.Now.IO (nowToIO)
 import Wire.Sem.Random.IO
+import Wire.ServiceStore.Cassandra (interpretServiceStoreToCassandra)
 import Wire.TeamCollaboratorsStore.Postgres (interpretTeamCollaboratorsStoreToPostgres)
 import Wire.TeamCollaboratorsSubsystem.Interpreter
 
@@ -267,6 +267,18 @@ evalGalley e =
         case (e ^. options . postgresMigration).conversation of
           CassandraStorage -> interpretConversationStoreToCassandra (e ^. cstate)
           PostgresqlStorage -> interpretConversationStoreToPostgres
+      localUnit = (toLocalUnsafe (e ^. options . settings . federationDomain) ())
+      backendNotificationQueueAccessEnv =
+        case e._rabbitmqChannel of
+          Nothing -> Nothing
+          Just chanMVar ->
+            Just
+              BackendNotificationQueueAccess.Env
+                { BackendNotificationQueueAccess.channelMVar = chanMVar,
+                  BackendNotificationQueueAccess.logger = e ^. applog,
+                  BackendNotificationQueueAccess.local = localUnit,
+                  BackendNotificationQueueAccess.requestId = e ^. reqId
+                }
    in ExceptT
         . runFinal @IO
         . resourceToIOFinal
@@ -293,7 +305,7 @@ evalGalley e =
         . interpretQueue (e ^. deleteQueue)
         . nowToIO
         . runInputConst (e ^. options)
-        . runInputConst (toLocalUnsafe (e ^. options . settings . federationDomain) ())
+        . runInputConst localUnit
         . interpretTeamFeatureSpecialContext e
         . runInputSem getAllTeamFeaturesForServer
         . interpretInternalTeamListToCassandra
@@ -305,7 +317,7 @@ evalGalley e =
         . convStoreInterpreter
         . interpretTeamStoreToCassandra lh
         . interpretTeamNotificationStoreToCassandra
-        . interpretServiceStoreToCassandra
+        . interpretServiceStoreToCassandra (e ^. cstate)
         . interpretSearchVisibilityStoreToCassandra
         . interpretLegalHoldStoreToCassandra lh
         . interpretCustomBackendStoreToCassandra
@@ -317,16 +329,17 @@ evalGalley e =
         . interpretClientStoreToCassandra
         . interpretTeamCollaboratorsStoreToPostgres
         . interpretFireAndForget
-        . interpretBackendNotificationQueueAccess
+        . BackendNotificationQueueAccess.interpretBackendNotificationQueueAccess backendNotificationQueueAccessEnv
         . interpretFederatorAccess
         . runRpcWithHttp (e ^. manager) (e ^. reqId)
         . runGundeckAPIAccess (e ^. options . gundeck)
         . interpretTeamSubsystem
+        . interpretBrigAccess (e ^. brig)
+        . interpretExternalAccess (e ^. extEnv)
         . runNotificationSubsystemGundeck (notificationSubsystemConfig e)
+        . interpretConversationSubsystem
         . interpretTeamCollaboratorsSubsystem
         . interpretSparAccess
-        . interpretBrigAccess (e ^. brig)
-        . interpretExternalAccess
   where
     lh = view (options . settings . featureFlags . to npProject) e
 
diff --git a/services/galley/src/Galley/Cassandra/Queries.hs b/services/galley/src/Galley/Cassandra/Queries.hs
index b143103b55..9b078d222b 100644
--- a/services/galley/src/Galley/Cassandra/Queries.hs
+++ b/services/galley/src/Galley/Cassandra/Queries.hs
@@ -23,7 +23,6 @@
 -- - legalhold_pending_prekeys
 -- - legalhold_service
 -- - legalhold_whitelisted
--- - service
 -- - team
 -- - team_admin
 -- - team_member
@@ -42,9 +41,6 @@ module Galley.Cassandra.Queries
     rmClients,
     selectSearchVisibility,
     updateSearchVisibility,
-    insertSrv,
-    selectSrv,
-    rmSrv,
     insertLegalHoldSettings,
     selectLegalHoldSettings,
     removeLegalHoldSettings,
@@ -286,17 +282,6 @@ upsertMemberRmClient c =
   let t = LT.fromStrict (clientToText c)
    in QueryString $ "update clients set clients = clients - {'" <> t <> "'} where user = ?"
 
--- Services -----------------------------------------------------------------
-
-rmSrv :: PrepQuery W (ProviderId, ServiceId) ()
-rmSrv = "delete from service where provider = ? AND id = ?"
-
-insertSrv :: PrepQuery W (ProviderId, ServiceId, HttpsUrl, ServiceToken, C.Set (Fingerprint Rsa), Bool) ()
-insertSrv = "insert into service (provider, id, base_url, auth_token, fingerprints, enabled) values (?, ?, ?, ?, ?, ?)"
-
-selectSrv :: PrepQuery R (ProviderId, ServiceId) (HttpsUrl, ServiceToken, C.Set (Fingerprint Rsa), Bool)
-selectSrv = "select base_url, auth_token, fingerprints, enabled from service where provider = ? AND id = ?"
-
 -- LegalHold ----------------------------------------------------------------
 
 insertLegalHoldSettings :: PrepQuery W (HttpsUrl, Fingerprint Rsa, ServiceToken, ServiceKey, TeamId) ()
diff --git a/services/galley/src/Galley/Effects.hs b/services/galley/src/Galley/Effects.hs
index 1d2811cbe5..4032d26edc 100644
--- a/services/galley/src/Galley/Effects.hs
+++ b/services/galley/src/Galley/Effects.hs
@@ -62,18 +62,14 @@ where
 
 import Data.Id
 import Data.Qualified
-import Galley.Effects.BackendNotificationQueueAccess
 import Galley.Effects.ClientStore
 import Galley.Effects.CodeStore
 import Galley.Effects.CustomBackendStore
-import Galley.Effects.ExternalAccess
 import Galley.Effects.FederatorAccess
-import Galley.Effects.FireAndForget
 import Galley.Effects.LegalHoldStore
 import Galley.Effects.ProposalStore
 import Galley.Effects.Queue
 import Galley.Effects.SearchVisibilityStore
-import Galley.Effects.ServiceStore
 import Galley.Effects.SparAccess
 import Galley.Effects.TeamFeatureStore
 import Galley.Effects.TeamMemberStore
@@ -89,8 +85,12 @@ import Polysemy.Input
 import Wire.API.Error
 import Wire.API.Error.Galley
 import Wire.API.Team.Feature
+import Wire.BackendNotificationQueueAccess
 import Wire.BrigAPIAccess
 import Wire.ConversationStore (ConversationStore, MLSCommitLockStore)
+import Wire.ConversationSubsystem
+import Wire.ExternalAccess
+import Wire.FireAndForget
 import Wire.GundeckAPIAccess
 import Wire.HashPassword
 import Wire.ListItems
@@ -100,17 +100,19 @@ import Wire.Rpc
 import Wire.Sem.Now
 import Wire.Sem.Paging.Cassandra
 import Wire.Sem.Random
+import Wire.ServiceStore
 import Wire.TeamCollaboratorsStore (TeamCollaboratorsStore)
 import Wire.TeamCollaboratorsSubsystem (TeamCollaboratorsSubsystem)
 import Wire.TeamSubsystem (TeamSubsystem)
 
 -- All the possible high-level effects.
 type GalleyEffects1 =
-  '[ ExternalAccess,
-     BrigAPIAccess,
-     SparAccess,
+  '[ SparAccess,
      TeamCollaboratorsSubsystem,
+     ConversationSubsystem,
      NotificationSubsystem,
+     ExternalAccess,
+     BrigAPIAccess,
      TeamSubsystem,
      GundeckAPIAccess,
      Rpc,
diff --git a/services/galley/src/Galley/Env.hs b/services/galley/src/Galley/Env.hs
index 51ea6f59fc..c4f0d3b34b 100644
--- a/services/galley/src/Galley/Env.hs
+++ b/services/galley/src/Galley/Env.hs
@@ -24,7 +24,7 @@ import Cassandra
 import Control.Lens hiding ((.=))
 import Data.ByteString.Conversion (toByteString')
 import Data.Id
-import Data.Misc (Fingerprint, HttpsUrl, Rsa)
+import Data.Misc (HttpsUrl)
 import Data.Range
 import Data.Time.Clock.DiffTime (millisecondsToDiffTime)
 import Galley.Aws qualified as Aws
@@ -44,6 +44,7 @@ import System.Logger
 import Util.Options
 import Wire.API.MLS.Keys
 import Wire.API.Team.Member
+import Wire.ExternalAccess.External
 import Wire.NotificationSubsystem.Interpreter
 import Wire.RateLimit.Interpreter (RateLimitEnv)
 
@@ -70,16 +71,8 @@ data Env = Env
     _passwordHashingRateLimitEnv :: RateLimitEnv
   }
 
--- | Environment specific to the communication with external
--- service providers.
-data ExtEnv = ExtEnv
-  { _extGetManager :: (Manager, [Fingerprint Rsa] -> Ssl.SSL -> IO ())
-  }
-
 makeLenses ''Env
 
-makeLenses ''ExtEnv
-
 -- TODO: somewhat duplicates Brig.App.initExtGetManager
 initExtEnv :: IO ExtEnv
 initExtEnv = do
diff --git a/services/galley/src/Galley/External/LegalHoldService/Internal.hs b/services/galley/src/Galley/External/LegalHoldService/Internal.hs
index 6cf5cabe5b..7fb6ecaa71 100644
--- a/services/galley/src/Galley/External/LegalHoldService/Internal.hs
+++ b/services/galley/src/Galley/External/LegalHoldService/Internal.hs
@@ -23,7 +23,7 @@ where
 
 import Bilge qualified
 import Bilge.Retry
-import Control.Lens (view)
+import Control.Lens ((^.))
 import Control.Monad.Catch
 import Control.Retry
 import Data.ByteString qualified as BS
@@ -38,6 +38,7 @@ import OpenSSL.Session qualified as SSL
 import Ssl.Util
 import System.Logger.Class qualified as Log
 import URI.ByteString (uriPath)
+import Wire.ExternalAccess.External (ExtEnv (..))
 
 -- | Check that the given fingerprint is valid and make the request over ssl.
 -- If the team has a device registered use 'makeLegalHoldServiceRequest' instead.
@@ -81,7 +82,8 @@ makeVerifiedRequest ::
   (Http.Request -> Http.Request) ->
   App (Http.Response LC8.ByteString)
 makeVerifiedRequest fpr url reqBuilder = do
-  (mgr, verifyFingerprints) <- view (extEnv . extGetManager)
+  env <- ask
+  let (mgr, verifyFingerprints) = extGetManager (env ^. extEnv)
   makeVerifiedRequestWithManager mgr verifyFingerprints fpr url reqBuilder
 
 -- | NOTE: Use this function wisely - this creates a new manager _every_ time it is called.
diff --git a/services/galley/src/Galley/Intra/BackendNotificationQueue.hs b/services/galley/src/Galley/Intra/BackendNotificationQueue.hs
deleted file mode 100644
index 756ce2379a..0000000000
--- a/services/galley/src/Galley/Intra/BackendNotificationQueue.hs
+++ /dev/null
@@ -1,105 +0,0 @@
-{-# LANGUAGE NumericUnderscores #-}
-
-module Galley.Intra.BackendNotificationQueue (interpretBackendNotificationQueueAccess) where
-
-import Control.Lens (view)
-import Control.Monad.Catch
-import Control.Monad.Trans.Except
-import Control.Retry
-import Data.Domain
-import Data.Qualified
-import Galley.Cassandra.Util
-import Galley.Effects.BackendNotificationQueueAccess (BackendNotificationQueueAccess (..))
-import Galley.Env
-import Galley.Monad
-import Galley.Options
-import Imports
-import Network.AMQP qualified as Q
-import Polysemy
-import Polysemy.Input
-import Polysemy.TinyLog
-import System.Logger.Class qualified as Log
-import UnliftIO
-import Wire.API.Federation.BackendNotifications
-import Wire.API.Federation.Error
-
-interpretBackendNotificationQueueAccess ::
-  ( Member (Embed IO) r,
-    Member (Input Env) r,
-    Member TinyLog r
-  ) =>
-  Sem (BackendNotificationQueueAccess ': r) a ->
-  Sem r a
-interpretBackendNotificationQueueAccess = interpret $ \case
-  EnqueueNotification deliveryMode remote action -> do
-    logEffect "BackendNotificationQueueAccess.EnqueueNotification"
-    embedApp . runExceptT $ enqueueNotification deliveryMode (tDomain remote) action
-  EnqueueNotificationsConcurrently m xs rpc -> do
-    logEffect "BackendNotificationQueueAccess.EnqueueNotificationsConcurrently"
-    embedApp . runExceptT $ enqueueNotificationsConcurrently m xs rpc
-  EnqueueNotificationsConcurrentlyBuckets m xs rpc -> do
-    logEffect "BackendNotificationQueueAccess.EnqueueNotificationsConcurrentlyBuckets"
-    embedApp . runExceptT $ enqueueNotificationsConcurrentlyBuckets m xs rpc
-
-getChannel :: ExceptT FederationError App (MVar Q.Channel)
-getChannel = view rabbitmqChannel >>= maybe (throwE FederationNotConfigured) pure
-
-enqueueSingleNotification :: Domain -> Q.DeliveryMode -> MVar Q.Channel -> FedQueueClient c a -> App a
-enqueueSingleNotification remoteDomain deliveryMode chanVar action = do
-  ownDomain <- view (options . settings . federationDomain)
-  let policy = limitRetries 3 <> constantDelay 1_000_000
-      handlers =
-        skipAsyncExceptions
-          <> [logRetries (const $ pure True) logError]
-  recovering policy handlers (const $ go ownDomain)
-  where
-    logError willRetry (SomeException e) status = do
-      rid <- view reqId
-      Log.err $
-        Log.msg @Text "failed to enqueue notification in RabbitMQ"
-          . Log.field "error" (displayException e)
-          . Log.field "willRetry" willRetry
-          . Log.field "retryCount" status.rsIterNumber
-          . Log.field "request" rid
-    go ownDomain = do
-      rid <- view reqId
-      mChan <- timeout 1_000_000 (readMVar chanVar)
-      case mChan of
-        Nothing -> throwM NoRabbitMqChannel
-        Just chan -> do
-          liftIO $ enqueue chan rid ownDomain remoteDomain deliveryMode action
-
-enqueueNotification :: Q.DeliveryMode -> Domain -> FedQueueClient c a -> ExceptT FederationError App a
-enqueueNotification deliveryMode remoteDomain action = do
-  chanVar <- getChannel
-  lift $ enqueueSingleNotification remoteDomain deliveryMode chanVar action
-
-enqueueNotificationsConcurrently ::
-  (Foldable f, Functor f) =>
-  Q.DeliveryMode ->
-  f (Remote x) ->
-  (Remote [x] -> FedQueueClient c a) ->
-  ExceptT FederationError App [Remote a]
-enqueueNotificationsConcurrently m xs f =
-  enqueueNotificationsConcurrentlyBuckets m (bucketRemote xs) f
-
-enqueueNotificationsConcurrentlyBuckets ::
-  (Foldable f) =>
-  Q.DeliveryMode ->
-  f (Remote x) ->
-  (Remote x -> FedQueueClient c a) ->
-  ExceptT FederationError App [Remote a]
-enqueueNotificationsConcurrentlyBuckets m xs f = do
-  case toList xs of
-    -- only attempt to get a channel if there is at least one notification to send
-    [] -> pure []
-    _ -> do
-      chanVar <- getChannel
-      lift $ pooledForConcurrentlyN 8 (toList xs) $ \r ->
-        qualifyAs r
-          <$> enqueueSingleNotification (tDomain r) m chanVar (f r)
-
-data NoRabbitMqChannel = NoRabbitMqChannel
-  deriving (Show)
-
-instance Exception NoRabbitMqChannel
diff --git a/services/galley/src/Galley/Options.hs b/services/galley/src/Galley/Options.hs
index bd5173f967..a435707a7e 100644
--- a/services/galley/src/Galley/Options.hs
+++ b/services/galley/src/Galley/Options.hs
@@ -74,7 +74,6 @@ import Data.Domain (Domain)
 import Data.Id (TeamId)
 import Data.Misc
 import Data.Range
-import Data.Text qualified as Text
 import Galley.Keys
 import Galley.Types.Teams
 import Hasql.Pool.Extended
@@ -86,6 +85,7 @@ import Util.Options.Common
 import Wire.API.Conversation.Protocol
 import Wire.API.Routes.Version
 import Wire.API.Team.Member
+import Wire.ConversationStore
 import Wire.RateLimit.Interpreter (RateLimitConfig)
 
 newtype GuestLinkTTLSeconds = GuestLinkTTLSeconds
@@ -188,22 +188,6 @@ deriveFromJSON toOptionFieldName ''JournalOpts
 
 makeLenses ''JournalOpts
 
-data StorageLocation = CassandraStorage | PostgresqlStorage
-
-instance FromJSON StorageLocation where
-  parseJSON = withText "StorageLocation" $ \case
-    "cassandra" -> pure CassandraStorage
-    "postgresql" -> pure PostgresqlStorage
-    x -> fail $ "Invalid storage location: " <> Text.unpack x <> ". Valid options: cassandra, postgresql"
-
-data PostgresMigrationOpts = PostgresMigrationOpts
-  { conversation :: StorageLocation
-  }
-
-instance FromJSON PostgresMigrationOpts where
-  parseJSON = withObject "PostgresMigrationOpts" $ \o ->
-    PostgresMigrationOpts <$> o .: "conversation"
-
 data Opts = Opts
   { -- | Host and port to bind to
     _galley :: !Endpoint,