diff --git a/docs/how-to/configure-the-build-base-for-an-expressjs-app.rst b/docs/how-to/configure-the-build-base-for-an-expressjs-app.rst
new file mode 100644
index 000000000..a0373289f
--- /dev/null
+++ b/docs/how-to/configure-the-build-base-for-an-expressjs-app.rst
@@ -0,0 +1,83 @@
+.. _configure-the-build-base-for-an-expressjs-app:
+
+Configure the build base for an ExpressJS app
+=============================================
+
+When using the ``expressjs-framework`` extension, there are four different cases
+for customising the Ubuntu base and the Node.js version to be included.
+The main differences between the cases are:
+
+- Whether to use the bare base or Ubuntu 24.04 base.
+- Whether Node.js is installed from Ubuntu package archive or the NPM plugin.
+
+The remainder of this page discusses the combinations of
+Ubuntu bases and sources for Node.js.
+
+Ubuntu 24.04 base, Node.js from Ubuntu package archive
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. code-block:: yaml
+    :caption: rockcraft.yaml
+
+    base: ubuntu@24.04
+    extensions:
+        - expressjs-framework
+
+In this case, the NPM plugin copies the app's files and installs its
+dependencies. Node.js then provides a runtime and launches the app. The NPM and
+Node.js versions are determined by the versions of NPM and Node.js shipped with
+the Ubuntu base. This `link to the Ubuntu archive
+<https://packages.ubuntu.com/noble/npm>`_ shows the NPM version shipped with the
+Ubuntu 24.04 base.
+
+Ubuntu 24.04 base, Node.js from NPM plugin
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. code-block:: yaml
+    :caption: rockcraft.yaml
+
+    base: ubuntu@24.04
+    extensions:
+        - expressjs-framework
+    parts:
+        expressjs-framework/install-app:
+            npm-include-node: true
+            npm-node-version: 20.12
+
+In this case, the NPM plugin copies the app's files and installs its
+dependencies. Node.js and NPM is installed by the NPM plugin.
+
+Bare base, Node.js from Ubuntu package archive
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. code-block:: yaml
+    :caption: rockcraft.yaml
+
+    base: bare
+    build-base: ubuntu@24.04
+    extensions:
+        - expressjs-framework
+
+In this case, the NPM plugin copies the app's files and installs its
+dependencies. Node.js then provides a runtime and launches the app. The NPM and
+Node.js versions are determined by the versions of NPM and Node.js shipped with
+the Ubuntu base.
+
+Bare base, Node.js from NPM plugin
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. code-block:: yaml
+    :caption: rockcraft.yaml
+
+    base: bare
+    build-base: ubuntu@24.04
+    parts:
+        expressjs-framework/install-app:
+            npm-include-node: true
+            npm-node-version: 20.12
+
+In this case, the NPM plugin copies the app's files and installs its
+dependencies. Node.js then provides a runtime and launches the app. Node.js and
+NPM is installed by the NPM plugin. For different possible values for the
+``npm-node-version`` key, refer to
+:ref:`NPM plugin documentation <craft_parts_npm_plugin>`.
diff --git a/docs/how-to/index.rst b/docs/how-to/index.rst
index b20dbafdc..49e1d37e8 100644
--- a/docs/how-to/index.rst
+++ b/docs/how-to/index.rst
@@ -40,6 +40,16 @@ compiled a couple of guides for you to facilitate your contribution.
 
    documentation <documentation/index>
 
+Extensions
+----------
+
+Learn how to use framework and platform extensions in your project.
+
+.. toctree::
+   :maxdepth: 1
+
+   configure-the-build-base-for-an-expressjs-app
+
 Rocks
 -----
 
diff --git a/docs/reference/extensions/expressjs-framework.rst b/docs/reference/extensions/expressjs-framework.rst
new file mode 100644
index 000000000..43bcda053
--- /dev/null
+++ b/docs/reference/extensions/expressjs-framework.rst
@@ -0,0 +1,54 @@
+.. _expressjs-framework-reference:
+
+expressjs-framework
+-------------------
+
+The ExpressJS extension streamlines the process of building ExpressJS
+application rocks.
+
+It facilitates the installation of ExpressJS application dependencies, including
+Node.js and NPM, inside the rock. Additionally, it transfers your project files
+to ``/app`` within the rock.
+
+The ExpressJS extension is compatible with the ``bare`` and ``ubuntu@24.04``
+bases.
+
+Project requirements
+====================
+
+There are 3 requirements to be able to use the ``expressjs-framework``
+extension:
+
+1. The application should reside in the ``app`` directory.
+2. The application should have a ``package.json`` file.
+3. The ``package.json`` file should define the ``start`` script.
+
+
+``parts`` > ``expressjs-framework/install-app`` > ``npm-include-node``
+======================================================================
+
+You can use this field to specify the version of Node.js to be installed. For
+example:
+
+.. code-block:: yaml
+
+  parts:
+    expressjs-framework/install-app:
+      npm-include-node: true
+      npm-node-version: 20.12.2
+
+For more examples of the ``npm-node-version`` key, see
+:ref:`craft_parts_npm_plugin`.
+
+If you don't customise the version of node, it will be installed from the Ubuntu
+package repository.
+
+``parts`` > ``expressjs-framework/runtime:`` > ``stage-packages``
+=================================================================
+
+Installing additional runtime packages is currently unsupported.
+
+See also
+========
+
+- :ref:`build-a-rock-for-an-expressjs-application`
diff --git a/docs/reference/extensions/index.rst b/docs/reference/extensions/index.rst
index 3bf8ae6c6..73a46dcce 100644
--- a/docs/reference/extensions/index.rst
+++ b/docs/reference/extensions/index.rst
@@ -15,3 +15,4 @@ initiating a new rock.
    django-framework
    fastapi-framework
    go-framework
+   expressjs-framework
diff --git a/docs/reference/rockcraft.yaml.rst b/docs/reference/rockcraft.yaml.rst
index b55a79ec8..8a41a9baa 100644
--- a/docs/reference/rockcraft.yaml.rst
+++ b/docs/reference/rockcraft.yaml.rst
@@ -268,6 +268,7 @@ Currently supported extensions:
 - ``django-framework``
 - ``go-framework``
 - ``fastapi-framework``
+- ``expressjs-framework``
 
 Example
 =======
diff --git a/docs/tutorial/code/django/task.yaml b/docs/tutorial/code/django/task.yaml
index 265517ecc..5fb42fb6f 100644
--- a/docs/tutorial/code/django/task.yaml
+++ b/docs/tutorial/code/django/task.yaml
@@ -26,7 +26,7 @@ execute: |
   retry -n 5 --wait 2 curl --fail localhost:8000
 
   # [docs:curl-django]
-  curl localhost:8000
+  curl --fail localhost:8000
   # [docs:curl-django-end]
 
   kill $!
@@ -62,7 +62,7 @@ execute: |
   retry -n 5 --wait 2 curl --fail localhost:8000
 
   # [docs:curl-django-rock]
-  curl localhost:8000
+  curl --fail localhost:8000
   # [docs:curl-django-rock-end]
 
   # [docs:get-logs]
@@ -100,7 +100,7 @@ execute: |
   retry -n 5 --wait 2 curl --fail localhost:8000
 
   # [docs:curl-django-bare-rock]
-  curl localhost:8000
+  curl --fail localhost:8000
   # [docs:curl-django-bare-rock-end]
 
   # [docs:stop-docker-chisel]
@@ -131,7 +131,7 @@ execute: |
   retry -n 5 --wait 2 curl --fail localhost:8000/time/
 
   # [docs:curl-time]
-  curl localhost:8000/time/
+  curl --fail localhost:8000/time/
   # [docs:curl-time-end]
 
   # [docs:stop-docker-updated]
diff --git a/docs/tutorial/code/expressjs/task.yaml b/docs/tutorial/code/expressjs/task.yaml
new file mode 100644
index 000000000..c1c2bd151
--- /dev/null
+++ b/docs/tutorial/code/expressjs/task.yaml
@@ -0,0 +1,117 @@
+###########################################
+# IMPORTANT
+# Comments matter!
+# The docs use the wrapping comments as
+# markers for including said instructions
+# as snippets in the docs.
+###########################################
+summary: Getting started with ExpressJS tutorial
+
+environment:
+
+execute: |
+  # [docs:install-deps]
+  sudo apt-get update -y && sudo apt-get install npm -y
+  # [docs:install-deps-end]
+
+  # [docs:init-app]
+  sudo npm install -g express-generator@4
+  express app
+  cd app && npm install
+  # [docs:init-app-end]
+
+  npm start &
+  cd ..
+  retry -n 5 --wait 2 curl --fail localhost:3000
+
+  # [docs:curl-expressjs]
+  curl --fail localhost:3000
+  # [docs:curl-expressjs-end]
+
+  kill $!
+  kill $(lsof -t -i:3000)
+
+  # [docs:create-rockcraft-yaml]
+  rockcraft init --profile expressjs-framework
+  # [docs:create-rockcraft-yaml-end]
+
+  sed -i "s/name: .*/name: expressjs-hello-world/g" rockcraft.yaml
+
+  # [docs:experimental]
+  export ROCKCRAFT_ENABLE_EXPERIMENTAL_EXTENSIONS=true
+  # [docs:experimental-end]
+
+  # [docs:pack]
+  rockcraft pack
+  # [docs:pack-end]
+
+  # [docs:ls-rock]
+  ls *.rock -l --block-size=MB
+  # [docs:ls-rock-end]
+
+  # [docs:skopeo-copy]
+  sudo rockcraft.skopeo --insecure-policy \
+    copy oci-archive:expressjs-hello-world_0.1_amd64.rock \
+    docker-daemon:expressjs-hello-world:0.1
+  # [docs:skopeo-copy-end]
+
+  # [docs:docker-images]
+  sudo docker images expressjs-hello-world:0.1
+  # [docs:docker-images-end]
+
+  # [docs:docker-run]
+  sudo docker run --rm -d -p 3000:3000 \
+    --name expressjs-hello-world expressjs-hello-world:0.1
+  # [docs:docker-run-end]
+  retry -n 5 --wait 2 curl --fail localhost:3000
+
+  # [docs:curl-expressjs-rock]
+  curl --fail localhost:3000
+  # [docs:curl-expressjs-rock-end]
+
+  # [docs:get-logs]
+  sudo docker exec expressjs-hello-world pebble logs expressjs
+  # [docs:get-logs-end]
+
+  # [docs:stop-docker]
+  sudo docker stop expressjs-hello-world
+  sudo docker rmi expressjs-hello-world:0.1
+  # [docs:stop-docker-end]
+
+  mv time.js app/routes/
+  original_line="var app = express();"
+  # Remove comments from time_app.js
+  sed -i 's:^//.*::g' time_app.js
+  append_line="$(cat time_app.js | tr '\n' ' ')"
+  sed -i "/$original_line/a$append_line" app/app.js
+  sed -i "s/version: .*/version: 0.2/g" rockcraft.yaml
+
+  # [docs:docker-run-update]
+  rockcraft pack
+  sudo rockcraft.skopeo --insecure-policy \
+    copy oci-archive:expressjs-hello-world_0.2_amd64.rock \
+    docker-daemon:expressjs-hello-world:0.2
+  sudo docker images expressjs-hello-world:0.2
+  sudo docker run --rm -d -p 3000:3000 \
+    --name expressjs-hello-world expressjs-hello-world:0.2
+  # [docs:docker-run-update-end]
+  retry -n 5 --wait 2 curl --fail localhost:3000/time
+
+  # [docs:curl-time]
+  curl --fail localhost:3000/time
+  # [docs:curl-time-end]
+
+  # [docs:stop-docker-updated]
+  sudo docker stop expressjs-hello-world
+  sudo docker rmi expressjs-hello-world:0.2
+  # [docs:stop-docker-updated-end]
+
+  # [docs:cleanup]
+  # delete all the files created during the tutorial
+  sudo npm uninstall -g express-generator@4
+  sudo apt-get remove npm -y
+  rm -rf app
+  rm expressjs-hello-world_0.1_amd64.rock \
+    expressjs-hello-world_0.2_amd64.rock \
+    rockcraft.yaml
+  # [docs:cleanup-end]
diff --git a/docs/tutorial/code/expressjs/time.js b/docs/tutorial/code/expressjs/time.js
new file mode 100644
index 000000000..eeb7c7ddd
--- /dev/null
+++ b/docs/tutorial/code/expressjs/time.js
@@ -0,0 +1,8 @@
+var express = require('express');
+var router = express.Router();
+
+router.get('/', function (req, res, next) {
+    res.send(Date());
+});
+
+module.exports = router;
diff --git a/docs/tutorial/code/expressjs/time_app.js b/docs/tutorial/code/expressjs/time_app.js
new file mode 100644
index 000000000..907026608
--- /dev/null
+++ b/docs/tutorial/code/expressjs/time_app.js
@@ -0,0 +1,4 @@
+// [docs:append-lines]
+var timeRouter = require('./routes/time');
+app.use('/time', timeRouter);
+// [docs:append-lines-end]
diff --git a/docs/tutorial/code/fastapi/task.yaml b/docs/tutorial/code/fastapi/task.yaml
index 4ef8fb497..53381ee8c 100644
--- a/docs/tutorial/code/fastapi/task.yaml
+++ b/docs/tutorial/code/fastapi/task.yaml
@@ -21,7 +21,7 @@ execute: |
   retry -n 5 --wait 2 curl --fail localhost:8000
 
   # [docs:curl-fastapi]
-  curl localhost:8000
+  curl --fail localhost:8000
   # [docs:curl-fastapi-end]
 
   kill $!
@@ -56,7 +56,7 @@ execute: |
   retry -n 5 --wait 2 curl --fail localhost:8000
 
   # [docs:curl-fastapi-rock]
-  curl localhost:8000
+  curl --fail localhost:8000
   # [docs:curl-fastapi-rock-end]
 
   # [docs:get-logs]
@@ -94,7 +94,7 @@ execute: |
   retry -n 5 --wait 2 curl --fail localhost:8000
 
   # [docs:curl-fastapi-bare-rock]
-  curl localhost:8000
+  curl --fail localhost:8000
   # [docs:curl-fastapi-bare-rock-end]
 
   # [docs:stop-docker-chisel]
@@ -117,7 +117,7 @@ execute: |
   retry -n 5 --wait 2 curl --fail localhost:8000/time
 
   # [docs:curl-time]
-  curl localhost:8000/time
+  curl --fail localhost:8000/time
   # [docs:curl-time-end]
 
   # [docs:stop-docker-updated]
diff --git a/docs/tutorial/code/flask/task.yaml b/docs/tutorial/code/flask/task.yaml
index dd54cd2dd..bfa4299ec 100644
--- a/docs/tutorial/code/flask/task.yaml
+++ b/docs/tutorial/code/flask/task.yaml
@@ -21,7 +21,7 @@ execute: |
   retry -n 5 --wait 2 curl --fail localhost:8000
 
   # [docs:curl-flask]
-  curl localhost:8000
+  curl --fail localhost:8000
   # [docs:curl-flask-end]
 
   kill $!
@@ -56,7 +56,7 @@ execute: |
   retry -n 5 --wait 2 curl --fail localhost:8000
 
   # [docs:curl-flask-rock]
-  curl localhost:8000
+  curl --fail localhost:8000
   # [docs:curl-flask-rock-end]
 
   # [docs:get-logs]
@@ -94,7 +94,7 @@ execute: |
   retry -n 5 --wait 2 curl --fail localhost:8000
 
   # [docs:curl-flask-bare-rock]
-  curl localhost:8000
+  curl --fail localhost:8000
   # [docs:curl-flask-bare-rock-end]
 
   # [docs:stop-docker-chisel]
@@ -118,7 +118,7 @@ execute: |
   retry -n 5 --wait 2 curl --fail localhost:8000/time
 
   # [docs:curl-time]
-  curl localhost:8000/time
+  curl --fail localhost:8000/time
   # [docs:curl-time-end]
 
   # [docs:stop-docker-updated]
diff --git a/docs/tutorial/django.rst b/docs/tutorial/django.rst
index 3aeac3526..bdd621b50 100644
--- a/docs/tutorial/django.rst
+++ b/docs/tutorial/django.rst
@@ -154,8 +154,7 @@ Check that the image was successfully loaded into Docker:
 The output should list the Django container image, along with its tag, ID and
 size:
 
-..  code-block:: text
-    :class: log-snippets
+.. terminal::
 
     REPOSITORY          TAG       IMAGE ID       CREATED       SIZE
     django-hello-world  0.1       5cd019b51db9   6 days ago   184MB
@@ -188,7 +187,7 @@ View the application logs
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
 When deploying the Django rock, we can always get the application logs via
-``pebble``:
+:ref:`pebble_explanation_page`:
 
 .. literalinclude:: code/django/task.yaml
     :language: text
@@ -196,12 +195,11 @@ When deploying the Django rock, we can always get the application logs via
     :end-before: [docs:get-logs-end]
     :dedent: 2
 
-As a result, :ref:`pebble_explanation_page` will give us the logs for the
+As a result, Pebble will give us the logs for the
 ``django`` service running inside the container.
 We should expect to see something similar to this:
 
-..  code-block:: text
-    :class: log-snippets
+.. terminal::
 
     2024-08-20T06:34:36.114Z [django] [2024-08-20 06:34:36 +0000] [17] [INFO] Starting gunicorn 23.0.0
     2024-08-20T06:34:36.115Z [django] [2024-08-20 06:34:36 +0000] [17] [INFO] Listening at: http://0.0.0.0:8000 (17)
@@ -288,7 +286,7 @@ and then using the same ``curl`` request:
     :end-before: [docs:curl-django-bare-rock-end]
     :dedent: 2
 
-Unsurprisingly, the Django application should still respond with
+The Django application should still respond with
 ``The install worked successfully! Congratulations!``.
 
 Cleanup
diff --git a/docs/tutorial/expressjs.rst b/docs/tutorial/expressjs.rst
new file mode 100644
index 000000000..3837ef9c8
--- /dev/null
+++ b/docs/tutorial/expressjs.rst
@@ -0,0 +1,334 @@
+.. _build-a-rock-for-an-expressjs-application:
+
+Build a rock for an ExpressJS application
+-----------------------------------------
+
+In this tutorial, we'll containerise a simple ExpressJS application into a rock
+using Rockcraft's ``expressjs-framework`` :ref:`extension
+<expressjs-framework-reference>`.
+
+It should take 25 minutes for you to complete.
+
+You won’t need to come prepared with intricate knowledge of software
+packaging, but familiarity with Linux paradigms, terminal operations,
+and ExpressJS is required.
+
+Once you complete this tutorial, you’ll have a working rock for an ExpressJS
+application. You’ll gain familiarity with Rockcraft and the
+``expressjs-framework`` extension, and have the experience to create
+rocks for ExpressJS applications.
+
+Setup
+=====
+
+.. include:: /reuse/tutorial/setup_edge.rst
+
+This tutorial requires the ``latest/edge`` channel of Rockcraft. Run
+``sudo snap refresh rockcraft --channel latest/edge`` to get the latest
+edge version.
+
+In order to test the ExpressJS application locally, before packing it into a
+rock, install ``npm`` and initialize the starter app.
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:install-deps]
+    :end-before: [docs:install-deps-end]
+    :dedent: 2
+
+
+Create the ExpressJS application
+================================
+
+Start by generating the ExpressJS starter template using the express-generator.
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:init-app]
+    :end-before: [docs:init-app-end]
+    :dedent: 2
+
+Let's Run the Express application to verify that it works:
+
+.. code:: bash
+
+  npm start
+
+The application starts an HTTP server listening on port 3000
+that we can test by using curl to send a request to the root
+endpoint. We may need a new terminal for this -- if using Multipass, run
+``multipass shell rock-dev`` to get another terminal:
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:curl-expressjs]
+    :end-before: [docs:curl-expressjs-end]
+    :dedent: 2
+
+The ExpressJS application should respond with *Welcome to Express* web page.
+
+.. note::
+    The response from the ExpressJS application includes HTML and CSS which
+    makes it difficult to read on a terminal. Visit ``http://localhost:3000``
+    using a browser to see the fully rendered page.
+
+The ExpressJS application looks good, so let's stop it for now
+with :kbd:`Ctrl` + :kbd:`C`, then move out of the application directory
+``cd ..``.
+
+Pack the Express application into a rock
+========================================
+
+First, we'll need a ``rockcraft.yaml`` project file. Rockcraft will automate its
+creation and tailor it for a ExpressJS application when we tell it to use the
+``expressjs-framework`` profile:
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:create-rockcraft-yaml]
+    :end-before: [docs:create-rockcraft-yaml-end]
+    :dedent: 2
+
+Open ``rockcraft.yaml`` in a text editor and check that the ``name``
+key is set to ``expressjs-hello-world``. Ensure that ``platforms`` includes
+the architecture of the host. For example, if the host uses the ARM
+architecture, include ``arm64`` in ``platforms``.
+
+As the ``expressjs-framework`` extension is still experimental, export the
+environment variable ``ROCKCRAFT_ENABLE_EXPERIMENTAL_EXTENSIONS``:
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:experimental]
+    :end-before: [docs:experimental-end]
+    :dedent: 2
+
+Pack the rock:
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:pack]
+    :end-before: [docs:pack-end]
+    :dedent: 2
+
+Depending on the network, this step can take a couple of minutes to finish.
+
+Once Rockcraft has finished packing the ExpressJS rock, we'll find a new file in
+the working directory (an `OCI <OCI_image_spec_>`_ image) with the ``.rock``
+extension:
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:ls-rock]
+    :end-before: [docs:ls-rock-end]
+    :dedent: 2
+
+
+Run the ExpressJS rock with Docker
+==================================
+
+We already have the rock as an OCI image. Load the image into Docker:
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:skopeo-copy]
+    :end-before: [docs:skopeo-copy-end]
+    :dedent: 2
+
+
+Check that the image was successfully loaded into Docker:
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:docker-images]
+    :end-before: [docs:docker-images-end]
+    :dedent: 2
+
+The output should list the ExpressJS image, along with its tag, ID and
+size:
+
+.. terminal::
+
+    REPOSITORY              TAG       IMAGE ID       CREATED       SIZE
+    expressjs-hello-world   0.1       30c7e5aed202   2 weeks ago   304MB
+
+Now we're finally ready to run the rock and test the containerised ExpressJS
+application:
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:docker-run]
+    :end-before: [docs:docker-run-end]
+    :dedent: 2
+
+Use the same curl command as before to send a request to the ExpressJS
+application's root endpoint which is running inside the container:
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:curl-expressjs-rock]
+    :end-before: [docs:curl-expressjs-rock-end]
+    :dedent: 2
+
+The ExpressJS application again responds with *Welcome to Express* page.
+
+View the application logs
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+When deploying the ExpressJS rock, we can always get the application logs with
+:ref:`pebble_explanation_page`:
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:get-logs]
+    :end-before: [docs:get-logs-end]
+    :dedent: 2
+
+As a result, Pebble will give us the logs for the
+``expressjs`` service running inside the container.
+We should expect to see something similar to this:
+
+.. terminal::
+
+    app@0.0.0 start
+    node ./bin/www
+    GET / 200 62.934 ms - 170
+
+We can also choose to follow the logs by using the ``-f`` option with the
+``pebble logs`` command above. To stop following the logs, press :kbd:`Ctrl` +
+:kbd:`C`.
+
+
+Stop the application
+~~~~~~~~~~~~~~~~~~~~
+
+Now we have a fully functional rock for a ExpressJS application! This concludes
+the first part of this tutorial, so we'll stop the container and remove the
+respective image for now:
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:stop-docker]
+    :end-before: [docs:stop-docker-end]
+    :dedent: 2
+
+
+Update the ExpressJS application
+================================
+
+For our final task, let's update our application. As an example,
+let's add a new ``/time`` endpoint that returns the current time.
+
+Start by creating the ``app/routes/time.js`` file in a text editor and paste the
+code from the snippet below:
+
+.. literalinclude:: code/expressjs/time.js
+    :caption: time.js
+    :language: javascript
+
+Place the code snippet below in ``app/app.js`` under routes registration section
+along with other ``app.use(...)`` lines.
+It will register the new ``/time`` endpoint:
+
+.. literalinclude:: code/expressjs/time_app.js
+    :caption: app.js
+    :language: javascript
+    :start-after: [docs:append-lines]
+    :end-before: [docs:append-lines-end]
+
+Since we are creating a new version of the application, set
+``version: '0.2'`` in the project file.
+
+Pack and run the rock using similar commands as before:
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:docker-run-update]
+    :end-before: [docs:docker-run-update-end]
+    :dedent: 2
+
+The resulting ``.rock`` file will be named differently, as
+its new version will be part of the filename.
+
+Finally, use curl to send a request to the ``/time`` endpoint:
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:curl-time]
+    :end-before: [docs:curl-time-end]
+    :dedent: 2
+
+The updated application should respond with the current date and time (e.g.
+``Fri Jan 10 2025 03:11:44 GMT+0000 (Coordinated Universal Time)``).
+
+.. tip::
+
+    If you are getting a ``404`` for the ``/time`` endpoint, check the
+    :ref:`troubleshooting-expressjs` steps below.
+
+Final Cleanup
+~~~~~~~~~~~~~
+
+We can now stop the container and remove the corresponding image:
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:stop-docker-updated]
+    :end-before: [docs:stop-docker-updated-end]
+    :dedent: 2
+
+Reset the environment
+=====================
+
+We've reached the end of this tutorial.
+
+If we'd like to reset the working environment, we can simply run the
+following:
+
+.. literalinclude:: code/expressjs/task.yaml
+    :language: bash
+    :start-after: [docs:cleanup]
+    :end-before: [docs:cleanup-end]
+    :dedent: 2
+
+.. collapse:: If using Multipass...
+
+    If we created an instance using Multipass, we can also clean it up.
+    Start by exiting it:
+
+    .. code-block:: bash
+
+        exit
+
+    And then we can proceed with its deletion:
+
+    .. code-block:: bash
+
+        multipass delete rock-dev
+        multipass purge
+
+----
+
+Next steps
+==========
+
+* :ref:`Rockcraft tutorials<tutorial>`.
+* :ref:`expressjs-framework reference<expressjs-framework-reference>`.
+* :ref:`why_use_rockcraft`.
+* :ref:`What is a Rock?<rocks_explanation>`.
+
+----
+
+.. _troubleshooting-expressjs:
+
+Troubleshooting
+===============
+
+**Application updates not taking effect?**
+
+Upon changing the ExpressJS application and re-packing the rock, if
+the changes are not taking effect, try running ``rockcraft clean`` and pack
+the rock again with ``rockcraft pack``.
+
+.. _`lxd-docker-connectivity-issue`: https://documentation.ubuntu.com/lxd/en/latest/howto/network_bridge_firewalld/#prevent-connectivity-issues-with-lxd-and-docker
+.. _`install-multipass`: https://multipass.run/docs/install-multipass
diff --git a/docs/tutorial/fastapi.rst b/docs/tutorial/fastapi.rst
index cc5598e0a..081459b0c 100644
--- a/docs/tutorial/fastapi.rst
+++ b/docs/tutorial/fastapi.rst
@@ -150,8 +150,7 @@ Check that the image was successfully loaded into Docker:
 The output should list the FastAPI container image, along with its tag, ID and
 size:
 
-..  code-block:: text
-    :class: log-snippets
+.. terminal::
 
     REPOSITORY            TAG       IMAGE ID       CREATED       SIZE
     fastapi-hello-world   0.1       30c7e5aed202   2 weeks ago   193MB
@@ -184,7 +183,7 @@ View the application logs
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
 When deploying the FastAPI rock, we can always get the application logs via
-``pebble``:
+:ref:`pebble_explanation_page`:
 
 .. literalinclude:: code/fastapi/task.yaml
     :language: text
@@ -192,12 +191,11 @@ When deploying the FastAPI rock, we can always get the application logs via
     :end-before: [docs:get-logs-end]
     :dedent: 2
 
-As a result, :ref:`pebble_explanation_page` will give us the logs for the
+As a result, Pebble will give us the logs for the
 ``fastapi`` service running inside the container.
 We should expect to see something similar to this:
 
-..  code-block:: text
-    :class: log-snippets
+.. terminal::
 
     2024-10-01T06:32:50.180Z [fastapi] INFO:     Started server process [12]
     2024-10-01T06:32:50.181Z [fastapi] INFO:     Waiting for application startup.
@@ -290,7 +288,7 @@ and then using the same ``curl`` request:
     :end-before: [docs:curl-fastapi-bare-rock-end]
     :dedent: 2
 
-Unsurprisingly, the FastAPI application should still respond with
+The FastAPI application should still respond with
 ``{"message":"Hello World"}``.
 
 Cleanup
diff --git a/docs/tutorial/flask.rst b/docs/tutorial/flask.rst
index 779dcb8c9..f6022713d 100644
--- a/docs/tutorial/flask.rst
+++ b/docs/tutorial/flask.rst
@@ -144,8 +144,7 @@ Check that the image was successfully loaded into Docker:
 The output should list the Flask container image, along with its tag, ID and
 size:
 
-..  code-block:: text
-    :class: log-snippets
+.. terminal::
 
     REPOSITORY          TAG       IMAGE ID       CREATED       SIZE
     flask-hello-world   0.1       c256056698ba   2 weeks ago   149MB
@@ -178,7 +177,7 @@ View the application logs
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
 When deploying the Flask rock, we can always get the application logs via
-``pebble``:
+:ref:`pebble_explanation_page`:
 
 .. literalinclude:: code/flask/task.yaml
     :language: text
@@ -186,12 +185,11 @@ When deploying the Flask rock, we can always get the application logs via
     :end-before: [docs:get-logs-end]
     :dedent: 2
 
-As a result, :ref:`pebble_explanation_page` will give us the logs for the
+As a result, Pebble will give us the logs for the
 ``flask`` service running inside the container.
 We expect to see something similar to this:
 
-..  code-block:: text
-    :class: log-snippets
+.. terminal::
 
     2024-06-21T03:41:45.077Z [flask] [2024-06-21 03:41:45 +0000] [17] [INFO] Starting gunicorn 22.0.0
     2024-06-21T03:41:45.077Z [flask] [2024-06-21 03:41:45 +0000] [17] [INFO] Listening at: http://0.0.0.0:8000 (17)
@@ -283,7 +281,7 @@ and then using the same ``curl`` request:
     :end-before: [docs:curl-flask-bare-rock-end]
     :dedent: 2
 
-Unsurprisingly, the Flask application should still respond with
+The Flask application should still respond with
 ``Hello, world!``.
 
 Cleanup
diff --git a/docs/tutorial/go.rst b/docs/tutorial/go.rst
index 812e5b226..3bb542721 100644
--- a/docs/tutorial/go.rst
+++ b/docs/tutorial/go.rst
@@ -176,8 +176,7 @@ Check that the image was successfully loaded into Docker:
 The output should list the Go container image, along with its tag, ID and
 size:
 
-..  code-block:: text
-    :class: log-snippets
+.. terminal::
 
     REPOSITORY       TAG       IMAGE ID       CREATED         SIZE
     go-hello-world   0.1       f3abf7ebc169   5 minutes ago   15.7MB
@@ -215,12 +214,11 @@ When deploying the Go rock, we can always get the application logs with
     :end-before: [docs:get-logs-end]
     :dedent: 2
 
-As a result, ``pebble`` will give the logs for the
+As a result, Pebble will give the logs for the
 ``go`` service running inside the container.
 We should expect to see something similar to this:
 
-..  code-block:: text
-    :class: log-snippets
+.. terminal::
 
     2024-10-04T08:51:35.826Z [go] 2024/10/04 08:51:35 starting hello world application
     2024-10-04T08:51:39.974Z [go] 2024/10/04 08:51:39 new hello world request
diff --git a/docs/tutorial/index.rst b/docs/tutorial/index.rst
index 315951f4a..374a11105 100644
--- a/docs/tutorial/index.rst
+++ b/docs/tutorial/index.rst
@@ -28,4 +28,4 @@ code into container applications:
    6. Build a rock for a Django application <django.rst>
    7. Build a rock for a FastAPI application <fastapi.rst>
    8. Build a rock for a Go application <go.rst>
-
+   9. Build a rock for an ExpressJS application <expressjs.rst>
diff --git a/rockcraft/extensions/__init__.py b/rockcraft/extensions/__init__.py
index 621619b56..015de6b0e 100644
--- a/rockcraft/extensions/__init__.py
+++ b/rockcraft/extensions/__init__.py
@@ -19,6 +19,7 @@
 from ._utils import apply_extensions
 from .fastapi import FastAPIFramework
 from .go import GoFramework
+from .expressjs import ExpressJSFramework
 from .gunicorn import DjangoFramework, FlaskFramework
 from .registry import get_extension_class, get_extension_names, register, unregister
 
@@ -31,6 +32,7 @@
 ]
 
 register("django-framework", DjangoFramework)
+register("expressjs-framework", ExpressJSFramework)
 register("fastapi-framework", FastAPIFramework)
 register("flask-framework", FlaskFramework)
 register("go-framework", GoFramework)
diff --git a/rockcraft/extensions/expressjs.py b/rockcraft/extensions/expressjs.py
new file mode 100644
index 000000000..846098dd7
--- /dev/null
+++ b/rockcraft/extensions/expressjs.py
@@ -0,0 +1,228 @@
+# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4 -*-
+#
+# Copyright 2024 Canonical Ltd.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""An extension for the NodeJS based Javascript application extension."""
+
+import json
+from typing import Any
+
+from overrides import override
+
+from ..errors import ExtensionError
+from .extension import Extension
+
+
+class ExpressJSFramework(Extension):
+    """An extension for constructing Javascript applications based on the ExpressJS framework."""
+
+    IMAGE_BASE_DIR = "app"
+
+    @staticmethod
+    @override
+    def get_supported_bases() -> tuple[str, ...]:
+        """Return supported bases."""
+        return "bare", "ubuntu@24.04"
+
+    @staticmethod
+    @override
+    def is_experimental(base: str | None) -> bool:
+        """Check if the extension is in an experimental state."""
+        return True
+
+    @override
+    def get_root_snippet(self) -> dict[str, Any]:
+        """Fill in some default root components.
+
+        Default values:
+          - run_user: _daemon_
+          - build-base: ubuntu@24.04
+          - platform: amd64
+          - services: a service to run the ExpressJS server
+          - parts: see ExpressJSFramework._gen_parts
+        """
+        self._check_project()
+
+        snippet: dict[str, Any] = {
+            "run-user": "_daemon_",
+            "services": {
+                "expressjs": {
+                    "override": "replace",
+                    "startup": "enabled",
+                    "user": "_daemon_",
+                    "working-dir": f"/{self.IMAGE_BASE_DIR}",
+                    "environment": {
+                        "NODE_ENV": "production",
+                    },
+                }
+            },
+        }
+        if not self.yaml_data.get("services", {}).get("expressjs", {}).get("command"):
+            snippet["services"]["expressjs"]["command"] = "npm start"
+
+        snippet["parts"] = {
+            "expressjs-framework/install-app": self._gen_install_app_part(),
+        }
+        runtime_part = self._gen_runtime_part()
+        if runtime_part:
+            snippet["parts"]["expressjs-framework/runtime"] = runtime_part
+        return snippet
+
+    @override
+    def get_part_snippet(self) -> dict[str, Any]:
+        """Return the part snippet to apply to existing parts.
+
+        This is unused but is required by the ABC.
+        """
+        return {}
+
+    @override
+    def get_parts_snippet(self) -> dict[str, Any]:
+        """Return the parts to add to parts.
+
+        This is unused but is required by the ABC.
+        """
+        return {}
+
+    def _check_project(self) -> None:
+        """Ensure this extension can apply to the current rockcraft project.
+
+        The ExpressJS framework assumes that:
+        - The npm start script exists.
+        - The application name is defined.
+        """
+        if (
+            "scripts" not in self._app_package_json
+            or "start" not in self._app_package_json["scripts"]
+        ):
+            raise ExtensionError(
+                "missing start script",
+                doc_slug="/reference/extensions/expressjs-framework",
+                logpath_report=False,
+            )
+        if "name" not in self._app_package_json or not isinstance(
+            self._app_package_json["name"], str
+        ):
+            raise ExtensionError(
+                "missing application name",
+                doc_slug="/reference/extensions/expressjs-framework",
+                logpath_report=False,
+            )
+
+    def _gen_install_app_part(self) -> dict:
+        """Generate the install app part using NPM plugin.
+
+        Set the script shell to bash and copy the .npmrc file to the app
+        directory. This is to ensure that the ExpressJS run in bare container
+        can use the shell to launch itself.
+        """
+        install_app_part: dict[str, Any] = {
+            "plugin": "npm",
+            "source": f"{self.IMAGE_BASE_DIR}/",
+            "override-build": (
+                "rm -rf node_modules\n"
+                "craftctl default\n"
+                "npm config set script-shell=bash --location project\n"
+                "cp ${CRAFT_PART_BUILD}/.npmrc ${CRAFT_PART_INSTALL}/lib/node_modules/"
+                f"{self._app_name}/.npmrc\n"
+                f"ln -s /lib/node_modules/{self._app_name} ${{CRAFT_PART_INSTALL}}/app\n"
+            ),
+        }
+        build_packages = self._gen_app_build_packages()
+        if build_packages:
+            install_app_part["build-packages"] = build_packages
+        stage_packages = self._gen_app_stage_packages()
+        if stage_packages:
+            install_app_part["stage-packages"] = stage_packages
+        if self._user_npm_include_node:
+            install_app_part["npm-include-node"] = self._user_npm_include_node
+            install_app_part["npm-node-version"] = self._user_install_app_part.get(
+                "npm-node-version"
+            )
+        return install_app_part
+
+    def _gen_app_build_packages(self) -> list[str]:
+        """Return the build packages for the install app part."""
+        if self._user_npm_include_node:
+            return []
+        return ["nodejs", "npm"]
+
+    def _gen_app_stage_packages(self) -> list[str]:
+        """Return the stage packages for the install app part."""
+        if self._rock_base == "bare":
+            return ["bash_bins", "ca-certificates_data", "coreutils_bins"]
+        if not self._user_npm_include_node:
+            return ["ca-certificates_data", "nodejs_bins"]
+        return ["ca-certificates_data"]
+
+    def _gen_runtime_part(self) -> dict | None:
+        """Generate the runtime part."""
+        stage_packages = []
+        if self._rock_base == "bare":
+            stage_packages = ["libstdc++6", "zlib1g"]
+        if not self._user_npm_include_node:
+            stage_packages.append("npm")
+        if not stage_packages:
+            return None
+        return {"plugin": "nil", "stage-packages": stage_packages}
+
+    @property
+    def _user_install_app_part(self) -> dict:
+        """Return the user defined install app part."""
+        return self.yaml_data.get("parts", {}).get(
+            "expressjs-framework/install-app", {}
+        )
+
+    @property
+    def _user_npm_include_node(self) -> bool:
+        """Return the user defined npm include node flag."""
+        return self._user_install_app_part.get("npm-include-node", False)
+
+    @property
+    def _rock_base(self) -> str:
+        """Return the base of the rockcraft project."""
+        return self.yaml_data["base"]
+
+    @property
+    def _app_package_json(self) -> dict:
+        """Return the app package.json contents."""
+        package_json_file = self.project_root / self.IMAGE_BASE_DIR / "package.json"
+        if not package_json_file.exists():
+            raise ExtensionError(
+                "missing package.json file",
+                doc_slug="/reference/extensions/expressjs-framework",
+                logpath_report=False,
+            )
+        package_json_contents = package_json_file.read_text(encoding="utf-8")
+        try:
+            app_package_json = json.loads(package_json_contents)
+            if not isinstance(app_package_json, dict):
+                raise ExtensionError(
+                    "invalid package.json file",
+                    doc_slug="/reference/extensions/expressjs-framework",
+                    logpath_report=False,
+                )
+            return app_package_json
+        except json.JSONDecodeError as exc:
+            raise ExtensionError(
+                "failed to parse package.json file",
+                doc_slug="/reference/extensions/expressjs-framework",
+                logpath_report=False,
+            ) from exc
+
+    @property
+    def _app_name(self) -> str:
+        """Return the application name as defined on package.json."""
+        return self._app_package_json["name"]
diff --git a/rockcraft/templates/expressjs-framework/rockcraft.yaml.j2 b/rockcraft/templates/expressjs-framework/rockcraft.yaml.j2
new file mode 100644
index 000000000..f116abba6
--- /dev/null
+++ b/rockcraft/templates/expressjs-framework/rockcraft.yaml.j2
@@ -0,0 +1,34 @@
+name: {{name}}
+# see {{versioned_url}}/explanation/bases/
+# for more information about bases and using 'bare' bases for chiselled rocks
+base: bare # as an alternative, a ubuntu base can be used
+build-base: ubuntu@24.04 # build-base is required when the base is bare
+version: '0.1' # just for humans. Semantic versioning is recommended
+summary: A summary of your ExpresssJS application # 79 char long summary
+description: |
+    This is {{name}}'s description. You have a paragraph or two to tell the
+    most important story about it. Keep it under 100 words though,
+    we live in tweetspace and your description wants to look good in the
+    container registries out there.
+# the platforms this rock should be built on and run on.
+# you can check your architecture with `dpkg --print-architecture`
+platforms:
+    amd64:
+    # arm64:
+    # ppc64el:
+    # s390x:
+
+# to ensure the expressjs-framework extension works properly, your ExpressJS
+# application should be inside the app directory and the "start" script defined
+# in the package.json's scripts section.
+extensions:
+    - expressjs-framework
+
+# uncomment the sections you need and adjust according to your requirements.
+# parts:  # you need to uncomment this line to add or update any part.
+#  expressjs-framework/install-app:
+#    # to specify the version of node to be installed, uncomment the following
+#    # line and set the version to the desired one.
+#    # see https://documentation.ubuntu.com/rockcraft/en/latest/common/craft-parts/reference/plugins/npm_plugin/
+#    npm-include-node: true
+#    npm-node-version: node
diff --git a/spread.yaml b/spread.yaml
index 80f78be62..4549f5dbd 100644
--- a/spread.yaml
+++ b/spread.yaml
@@ -17,6 +17,8 @@ include:
   - pyproject.toml
   - rockcraft/
 
+# The default spread timeout is 15 minutes. This is too short for some tests.
+kill-timeout: 25m
 backends:
   google:
     key: '$(HOST: echo "$SPREAD_GOOGLE_KEY")'
diff --git a/tests/spread/rockcraft/extension-expressjs/task.yaml b/tests/spread/rockcraft/extension-expressjs/task.yaml
new file mode 100644
index 000000000..9b77ff5c9
--- /dev/null
+++ b/tests/spread/rockcraft/extension-expressjs/task.yaml
@@ -0,0 +1,71 @@
+summary: expressjs extension test
+environment:
+  SCENARIO/bare: bare
+  SCENARIO/base_2404: ubuntu-24.04
+  ROCKCRAFT_ENABLE_EXPERIMENTAL_EXTENSIONS: "true"
+
+execute: |
+  NAME="expressjs-${SCENARIO//./-}"
+  ROCK_FILE="${NAME}_0.1_amd64.rock"
+  IMAGE="${NAME}:0.1"
+
+  sudo apt-get update -y && sudo apt-get install npm -y
+  npm install -g express-generator@4
+  express app
+  cd app && npm install && cd ..
+
+  run_rockcraft init --name "${NAME}" --profile expressjs-framework
+  sed -i "s/^base: .*/base: ${SCENARIO//-/@}/g" rockcraft.yaml
+  if [ "${SCENARIO}" != "bare" ]; then
+    sed -i "s/^build-base: .*/build-base: ${SCENARIO//-/@}/g" rockcraft.yaml
+  fi
+
+  function run_test() {
+    # rockcraft clean is required here because the cached layer writes to npmrc
+    # multiple times, causing the app to crash on first run.
+    rockcraft clean
+    run_rockcraft pack
+
+    test -f "${ROCK_FILE}"
+    test ! -d work
+
+    # Ensure docker does not have this container image
+    docker rmi --force "${IMAGE}"
+    # Install container
+    sudo rockcraft.skopeo --insecure-policy copy "oci-archive:${ROCK_FILE}" \
+    "docker-daemon:${IMAGE}"
+    # Ensure container exists
+    docker images "${IMAGE}" | MATCH "${NAME}"
+
+    # Ensure container doesn't exist
+    docker rm -f "${NAME}-container"
+
+    # test the default expressjs service
+    docker run --name "${NAME}-container" -d -p 8137:3000 "${IMAGE}"
+    retry -n 5 --wait 2 curl localhost:8137
+    http_status=$(curl -s -o /dev/null -w "%{http_code}" localhost:8137)
+    [ "${http_status}" -eq 200 ]
+  }
+
+  run_test
+
+  # test the expressjs service with a Node version specified
+  node_version=20.18.2
+  cat <<EOF >> rockcraft.yaml
+  parts:
+    expressjs-framework/install-app:
+      npm-include-node: true
+      npm-node-version: $node_version
+  EOF
+  run_test
+
+  container_id=$(docker ps -q -f name="${NAME}-container")
+  container_node_version=$(sudo docker exec $container_id node --version)
+  [ "$container_node_version" = "v$node_version" ]
+
+restore: |
+  NAME="expressjs-${SCENARIO//./-}"
+  docker stop "${NAME}-container"
+  docker rm "${NAME}-container"
+  rm -f "*.rock" rockcraft.yaml
+  docker system prune -a -f
diff --git a/tests/spread/rockcraft/extension-go/task.yaml b/tests/spread/rockcraft/extension-go/task.yaml
index 1fdcd7916..55aaf803a 100644
--- a/tests/spread/rockcraft/extension-go/task.yaml
+++ b/tests/spread/rockcraft/extension-go/task.yaml
@@ -10,7 +10,6 @@ execute: |
   IMAGE="${NAME}:0.1"
 
   run_rockcraft init --name "${NAME}" --profile go-framework
-  sed -i "s/^name: .*/name: ${NAME}/g" rockcraft.yaml
   sed -i "s/^base: .*/base: ${SCENARIO//-/@}/g" rockcraft.yaml
   if [ "${SCENARIO}" != "bare" ]; then
     sed -i "s/^build-base: .*/build-base: ${SCENARIO//-/@}/g" rockcraft.yaml
@@ -25,7 +24,8 @@ execute: |
   # Ensure docker does not have this container image
   docker rmi --force "${IMAGE}"
   # Install container
-  sudo rockcraft.skopeo --insecure-policy copy "oci-archive:${ROCK_FILE}" "docker-daemon:${IMAGE}"
+  sudo rockcraft.skopeo --insecure-policy copy "oci-archive:${ROCK_FILE}" \
+    "docker-daemon:${IMAGE}"
   # Ensure container exists
   docker images "${IMAGE}" | MATCH "${NAME}"
 
diff --git a/tests/unit/extensions/test_expressjs.py b/tests/unit/extensions/test_expressjs.py
new file mode 100644
index 000000000..96b22a296
--- /dev/null
+++ b/tests/unit/extensions/test_expressjs.py
@@ -0,0 +1,322 @@
+# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4 -*-
+#
+# Copyright 2024 Canonical Ltd.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 3 as
+# published by the Free Software Foundation.
+#
+# 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+import pytest
+from rockcraft import extensions
+from rockcraft.errors import ExtensionError
+
+_expressjs_project_name = "test-expressjs-project"
+
+
+@pytest.fixture(name="expressjs_input_yaml")
+def expressjs_input_yaml_fixture():
+    return {
+        "name": "foo-bar",
+        "base": "ubuntu@24.04",
+        "build-base": "ubuntu@24.04",
+        "platforms": {"amd64": {}},
+        "extensions": ["expressjs-framework"],
+    }
+
+
+@pytest.fixture
+def expressjs_extension(mock_extensions, monkeypatch):
+    monkeypatch.setenv("ROCKCRAFT_ENABLE_EXPERIMENTAL_EXTENSIONS", "1")
+    extensions.register("expressjs-framework", extensions.ExpressJSFramework)
+
+
+@pytest.fixture
+def app_path(tmp_path):
+    app_path = tmp_path / "app"
+    app_path.mkdir(parents=True, exist_ok=True)
+    return app_path
+
+
+@pytest.fixture
+def package_json_file(app_path):
+    (app_path / "package.json").write_text(
+        f"""{{
+    "name": "{_expressjs_project_name}",
+    "scripts": {{
+        "start": "node ./bin/www"
+    }}
+}}"""
+    )
+
+
+@pytest.mark.parametrize(
+    "base, npm_include_node, node_version, expected_yaml_dict",
+    [
+        pytest.param(
+            "ubuntu@24.04",
+            False,
+            None,
+            {
+                "base": "ubuntu@24.04",
+                "build-base": "ubuntu@24.04",
+                "name": "foo-bar",
+                "platforms": {
+                    "amd64": {},
+                },
+                "run-user": "_daemon_",
+                "parts": {
+                    "expressjs-framework/install-app": {
+                        "plugin": "npm",
+                        "source": "app/",
+                        "npm-include-node": False,
+                        "npm-node-version": None,
+                        "override-build": (
+                            "rm -rf node_modules\n"
+                            "craftctl default\n"
+                            "npm config set script-shell=bash --location project\n"
+                            "cp ${CRAFT_PART_BUILD}/.npmrc ${CRAFT_PART_INSTALL}/lib/node_modules/"
+                            f"{_expressjs_project_name}/.npmrc\n"
+                            f"ln -s /lib/node_modules/{_expressjs_project_name} "
+                            "${CRAFT_PART_INSTALL}/app\n"
+                        ),
+                        "build-packages": ["nodejs", "npm"],
+                        "stage-packages": ["ca-certificates_data", "nodejs_bins"],
+                    },
+                    "expressjs-framework/runtime": {
+                        "plugin": "nil",
+                        "stage-packages": ["npm"],
+                    },
+                },
+                "services": {
+                    "expressjs": {
+                        "override": "replace",
+                        "startup": "enabled",
+                        "user": "_daemon_",
+                        "working-dir": "/app",
+                        "command": "npm start",
+                        "environment": {"NODE_ENV": "production"},
+                    },
+                },
+            },
+            id="ubuntu@24.04",
+        ),
+        pytest.param(
+            "ubuntu@24.04",
+            True,
+            "1.0.0",
+            {
+                "base": "ubuntu@24.04",
+                "build-base": "ubuntu@24.04",
+                "name": "foo-bar",
+                "parts": {
+                    "expressjs-framework/install-app": {
+                        "npm-include-node": True,
+                        "npm-node-version": "1.0.0",
+                        "override-build": "rm -rf node_modules\n"
+                        "craftctl default\n"
+                        "npm config set script-shell=bash --location project\n"
+                        "cp ${CRAFT_PART_BUILD}/.npmrc "
+                        "${CRAFT_PART_INSTALL}/lib/node_modules/test-expressjs-project/.npmrc\n"
+                        "ln -s /lib/node_modules/test-expressjs-project "
+                        "${CRAFT_PART_INSTALL}/app\n",
+                        "plugin": "npm",
+                        "source": "app/",
+                        "stage-packages": ["ca-certificates_data"],
+                    }
+                },
+                "platforms": {
+                    "amd64": {},
+                },
+                "run-user": "_daemon_",
+                "services": {
+                    "expressjs": {
+                        "command": "npm start",
+                        "environment": {
+                            "NODE_ENV": "production",
+                        },
+                        "override": "replace",
+                        "startup": "enabled",
+                        "user": "_daemon_",
+                        "working-dir": "/app",
+                    },
+                },
+            },
+            id="ubuntu@24.04",
+        ),
+        pytest.param(
+            "bare",
+            False,
+            None,
+            {
+                "base": "bare",
+                "build-base": "ubuntu@24.04",
+                "name": "foo-bar",
+                "parts": {
+                    "expressjs-framework/install-app": {
+                        "build-packages": [
+                            "nodejs",
+                            "npm",
+                        ],
+                        "npm-include-node": False,
+                        "npm-node-version": None,
+                        "override-build": "rm -rf node_modules\n"
+                        "craftctl default\n"
+                        "npm config set script-shell=bash --location project\n"
+                        "cp ${CRAFT_PART_BUILD}/.npmrc "
+                        "${CRAFT_PART_INSTALL}/lib/node_modules/test-expressjs-project/.npmrc\n"
+                        "ln -s /lib/node_modules/test-expressjs-project "
+                        "${CRAFT_PART_INSTALL}/app\n",
+                        "plugin": "npm",
+                        "source": "app/",
+                        "stage-packages": [
+                            "bash_bins",
+                            "ca-certificates_data",
+                            "coreutils_bins",
+                        ],
+                    },
+                    "expressjs-framework/runtime": {
+                        "plugin": "nil",
+                        "stage-packages": [
+                            "libstdc++6",
+                            "zlib1g",
+                            "npm",
+                        ],
+                    },
+                },
+                "platforms": {
+                    "amd64": {},
+                },
+                "run-user": "_daemon_",
+                "services": {
+                    "expressjs": {
+                        "command": "npm start",
+                        "environment": {
+                            "NODE_ENV": "production",
+                        },
+                        "override": "replace",
+                        "startup": "enabled",
+                        "user": "_daemon_",
+                        "working-dir": "/app",
+                    },
+                },
+            },
+            id="ubuntu@24.04",
+        ),
+        pytest.param(
+            "bare",
+            True,
+            "1.0.0",
+            {
+                "base": "bare",
+                "build-base": "ubuntu@24.04",
+                "name": "foo-bar",
+                "parts": {
+                    "expressjs-framework/install-app": {
+                        "npm-include-node": True,
+                        "npm-node-version": "1.0.0",
+                        "override-build": "rm -rf node_modules\n"
+                        "craftctl default\n"
+                        "npm config set script-shell=bash --location project\n"
+                        "cp ${CRAFT_PART_BUILD}/.npmrc "
+                        "${CRAFT_PART_INSTALL}/lib/node_modules/test-expressjs-project/.npmrc\n"
+                        "ln -s /lib/node_modules/test-expressjs-project "
+                        "${CRAFT_PART_INSTALL}/app\n",
+                        "plugin": "npm",
+                        "source": "app/",
+                        "stage-packages": [
+                            "bash_bins",
+                            "ca-certificates_data",
+                            "coreutils_bins",
+                        ],
+                    },
+                    "expressjs-framework/runtime": {
+                        "plugin": "nil",
+                        "stage-packages": ["libstdc++6", "zlib1g"],
+                    },
+                },
+                "platforms": {
+                    "amd64": {},
+                },
+                "run-user": "_daemon_",
+                "services": {
+                    "expressjs": {
+                        "command": "npm start",
+                        "environment": {
+                            "NODE_ENV": "production",
+                        },
+                        "override": "replace",
+                        "startup": "enabled",
+                        "user": "_daemon_",
+                        "working-dir": "/app",
+                    },
+                },
+            },
+            id="ubuntu@24.04",
+        ),
+    ],
+)
+@pytest.mark.usefixtures("expressjs_extension", "package_json_file")
+def test_expressjs_extension_default(
+    tmp_path,
+    expressjs_input_yaml,
+    base,
+    npm_include_node,
+    node_version,
+    expected_yaml_dict,
+):
+    expressjs_input_yaml["base"] = base
+    expressjs_input_yaml["parts"] = {
+        "expressjs-framework/install-app": {
+            "npm-include-node": npm_include_node,
+            "npm-node-version": node_version,
+        }
+    }
+    applied = extensions.apply_extensions(tmp_path, expressjs_input_yaml)
+
+    assert applied == expected_yaml_dict
+
+
+@pytest.mark.usefixtures("expressjs_extension")
+def test_expressjs_no_package_json_error(tmp_path, expressjs_input_yaml):
+    with pytest.raises(ExtensionError) as exc:
+        extensions.apply_extensions(tmp_path, expressjs_input_yaml)
+    assert str(exc.value) == "missing package.json file"
+    assert str(exc.value.doc_slug) == "/reference/extensions/expressjs-framework"
+
+
+@pytest.mark.parametrize(
+    "package_json_path, package_json_contents, error_message",
+    [
+        ("invalid-path", "", "missing package.json file"),
+        ("package.json", "[]", "invalid package.json file"),
+        ("package.json", "{", "failed to parse package.json file"),
+        ("package.json", "{}", "missing start script"),
+        ("package.json", '{"scripts":{}}', "missing start script"),
+        (
+            "package.json",
+            '{"scripts":{"start":"node ./bin/www"}}',
+            "missing application name",
+        ),
+    ],
+)
+@pytest.mark.usefixtures("expressjs_extension")
+def test_expressjs_invalid_package_json_scripts_error(
+    tmp_path,
+    app_path,
+    expressjs_input_yaml,
+    package_json_path,
+    package_json_contents,
+    error_message,
+):
+    (app_path / package_json_path).write_text(package_json_contents)
+    with pytest.raises(ExtensionError) as exc:
+        extensions.apply_extensions(tmp_path, expressjs_input_yaml)
+    assert str(exc.value) == error_message
+    assert str(exc.value.doc_slug) == "/reference/extensions/expressjs-framework"