diff --git a/lib/realtime-events.ts b/lib/realtime-events.ts
index fa820e6..d7e88cf 100644
--- a/lib/realtime-events.ts
+++ b/lib/realtime-events.ts
@@ -2,9 +2,19 @@ import type { PrismaClient } from "@prisma/client"
 
 import { enqueueRealtimeEvent } from "@/lib/realtime-queue"
 
-type PrismaMiddleware = Parameters<PrismaClient["$use"]>[0]
-type PrismaMiddlewareParams = Parameters<PrismaMiddleware>[0]
-type PrismaMiddlewareNext = Parameters<PrismaMiddleware>[1]
+type PrismaMiddlewareParams = {
+  action: string
+  model?: string | null
+  args?: unknown
+  [key: string]: unknown
+}
+
+type PrismaMiddlewareNext = (params: PrismaMiddlewareParams) => Promise<unknown>
+
+type PrismaMiddleware = (
+  params: PrismaMiddlewareParams,
+  next: PrismaMiddlewareNext,
+) => Promise<unknown>
 
 const MUTATION_ACTIONS = new Set([
   "create",
diff --git a/lib/realtime-queue.ts b/lib/realtime-queue.ts
index c925308..bc7709a 100644
--- a/lib/realtime-queue.ts
+++ b/lib/realtime-queue.ts
@@ -1,5 +1,5 @@
 import { Queue, Worker } from "bullmq"
-import type { JobsOptions } from "bullmq"
+import type { Job, JobsOptions } from "bullmq"
 
 import { createRedisConnection, getRedisUrl } from "@/lib/redis"
 import { getRealtimeIO } from "@/lib/realtime"
@@ -47,7 +47,7 @@ function ensureWorker() {
   if (!globalForQueue.realtimeWorker) {
     globalForQueue.realtimeWorker = new Worker(
       queueName,
-      async job => {
+      async (job: Job) => {
         const io = getRealtimeIO()
 
         if (io) {
@@ -64,7 +64,7 @@ function ensureWorker() {
       { connection },
     )
 
-    globalForQueue.realtimeWorker.on("error", error => {
+    globalForQueue.realtimeWorker.on("error", (error: Error) => {
       console.error("Realtime worker error", error)
     })
   }
diff --git a/pages/api/socket/io.ts b/pages/api/socket/io.ts
index a9c4ebb..052c849 100644
--- a/pages/api/socket/io.ts
+++ b/pages/api/socket/io.ts
@@ -1,5 +1,6 @@
 import type { NextApiRequest } from "next"
 import { Server as IOServer } from "socket.io"
+import type { DisconnectReason, Socket } from "socket.io"
 
 import type { NextApiResponseServerIO } from "@/types/next"
 import { getRealtimeIO, setRealtimeIO } from "@/lib/realtime"
@@ -24,14 +25,14 @@ export default function handler(req: NextApiRequest, res: NextApiResponseServerI
     setRealtimeIO(io)
     existingServer.io = io
 
-    io.on("connection", socket => {
+    io.on("connection", (socket: Socket) => {
       socket.emit("realtime:event", {
         event: "socket:connected",
         socketId: socket.id,
         timestamp: Date.now(),
       })
 
-      socket.on("disconnect", reason => {
+      socket.on("disconnect", (reason: DisconnectReason) => {
         socket.broadcast.emit("realtime:event", {
           event: "socket:disconnected",
           socketId: socket.id,
diff --git a/types/external.d.ts b/types/external.d.ts
new file mode 100644
index 0000000..13d6813
--- /dev/null
+++ b/types/external.d.ts
@@ -0,0 +1,103 @@
+declare module "socket.io-client" {
+  export interface Socket {
+    id: string
+    emit(event: string, ...args: unknown[]): void
+    on(event: string, listener: (...args: unknown[]) => void): this
+    off(event: string, listener: (...args: unknown[]) => void): this
+    connect(): void
+    disconnect(): void
+    broadcast?: {
+      emit(event: string, ...args: unknown[]): void
+    }
+  }
+
+  export interface SocketOptions {
+    path?: string
+    transports?: string[]
+    autoConnect?: boolean
+    reconnection?: boolean
+    reconnectionDelay?: number
+    reconnectionDelayMax?: number
+  }
+
+  export function io(opts?: SocketOptions): Socket
+  export function io(uri: string, opts?: SocketOptions): Socket
+  export { io }
+  export default io
+}
+
+declare module "socket.io" {
+  import type { Server as HTTPServer } from "http"
+
+  export interface ServerOptions {
+    path?: string
+    cors?: {
+      origin?: string | string[]
+    }
+  }
+
+  export interface BroadcastOperator {
+    emit(event: string, ...args: unknown[]): void
+  }
+
+  export type DisconnectReason = string
+
+  export interface Socket {
+    id: string
+    emit(event: string, ...args: unknown[]): void
+    on(event: "disconnect", listener: (reason: DisconnectReason) => void): this
+    on(event: string, listener: (...args: unknown[]) => void): this
+    broadcast: BroadcastOperator
+  }
+
+  export class Server {
+    constructor(httpServer?: HTTPServer, opts?: ServerOptions)
+    emit(event: string, ...args: unknown[]): boolean
+    on(event: "connection", listener: (socket: Socket) => void): this
+    on(event: string, listener: (...args: unknown[]) => void): this
+  }
+
+  export { Server as IOServer }
+}
+
+declare module "bullmq" {
+  export interface JobsOptions {
+    removeOnComplete?: boolean | { age?: number; count?: number }
+    removeOnFail?: boolean | { age?: number; count?: number }
+    [key: string]: unknown
+  }
+
+  export interface QueueOptions {
+    connection?: unknown
+  }
+
+  export interface WorkerOptions {
+    connection?: unknown
+  }
+
+  export interface Job<Data = unknown> {
+    id?: string | number
+    name: string
+    data: Data
+  }
+
+  export class Queue<Data = unknown, Result = unknown, Name extends string = string> {
+    constructor(name: Name, opts?: QueueOptions)
+    add(name: Name, data: Data, opts?: JobsOptions): Promise<Job<Data>>
+  }
+
+  export class Worker<Data = unknown, Name extends string = string> {
+    constructor(name: Name, processor: (job: Job<Data>) => Promise<unknown>, opts?: WorkerOptions)
+    on(event: "error", handler: (error: Error) => void): this
+  }
+}
+
+declare module "ioredis" {
+  export interface RedisOptions {
+    [key: string]: unknown
+  }
+
+  export default class IORedis {
+    constructor(url?: string, options?: RedisOptions)
+  }
+}