diff --git a/src/client/actions/CallActions.test.ts b/src/client/actions/CallActions.test.ts
index 8da26eb..8d03a08 100644
--- a/src/client/actions/CallActions.test.ts
+++ b/src/client/actions/CallActions.test.ts
@@ -46,7 +46,7 @@ describe('CallActions', () => {
 
     it('calls handshake.init when connected & got camera stream', async () => {
       const promise = callActions.init()
-      socket.emit('connect')
+      socket.emit('connect', undefined)
       await promise
       expect(store.getState().allActions.slice(1)).toEqual([{
         type: constants.NOTIFY,
@@ -73,8 +73,8 @@ describe('CallActions', () => {
 
     it('calls dispatches disconnect message on disconnect', async () => {
       const promise = callActions.init()
-      socket.emit('connect')
-      socket.emit('disconnect')
+      socket.emit('connect', undefined)
+      socket.emit('disconnect', undefined)
       expect(store.getState().allActions.slice(1)).toEqual([{
         type: constants.NOTIFY,
         payload: {
@@ -96,7 +96,7 @@ describe('CallActions', () => {
     it('dispatches alert when failed to get media stream', async () => {
       (getUserMedia as any).fail(true)
       const promise = callActions.init()
-      socket.emit('connect')
+      socket.emit('connect', undefined)
       await promise
     })
 
diff --git a/src/client/actions/CallActions.ts b/src/client/actions/CallActions.ts
index 3201db0..8b8ba61 100644
--- a/src/client/actions/CallActions.ts
+++ b/src/client/actions/CallActions.ts
@@ -2,6 +2,7 @@ import * as constants from '../constants'
 import socket from '../socket'
 import { Dispatch, ThunkResult } from '../store'
 import { callId, getUserMedia } from '../window'
+import { ClientSocket } from '../socket'
 import * as NotifyActions from './NotifyActions'
 import * as SocketActions from './SocketActions'
 import * as StreamActions from './StreamActions'
@@ -34,7 +35,7 @@ async (dispatch, getState) => {
 }
 
 export const connect = () => (dispatch: Dispatch) => {
-  return new Promise<SocketIOClient.Socket>(resolve => {
+  return new Promise<ClientSocket>(resolve => {
     socket.once('connect', () => {
       resolve(socket)
     })
diff --git a/src/client/actions/PeerActions.test.ts b/src/client/actions/PeerActions.test.ts
index b41895f..91441d7 100644
--- a/src/client/actions/PeerActions.test.ts
+++ b/src/client/actions/PeerActions.test.ts
@@ -7,15 +7,16 @@ import { EventEmitter } from 'events'
 import { createStore, Store, GetState } from '../store'
 import { play } from '../window'
 import { Dispatch } from 'redux'
+import { ClientSocket } from '../socket'
 
 describe('PeerActions', () => {
   function createSocket () {
-    const socket = new EventEmitter() as unknown as SocketIOClient.Socket
+    const socket = new EventEmitter() as unknown as ClientSocket
     socket.id = 'user1'
     return socket
   }
 
-  let socket: SocketIOClient.Socket
+  let socket: ClientSocket
   let stream: MediaStream
   let user: { id: string }
   let store: Store
diff --git a/src/client/actions/PeerActions.ts b/src/client/actions/PeerActions.ts
index 502dcbb..59ff633 100644
--- a/src/client/actions/PeerActions.ts
+++ b/src/client/actions/PeerActions.ts
@@ -2,11 +2,12 @@ import * as ChatActions from '../actions/ChatActions'
 import * as NotifyActions from '../actions/NotifyActions'
 import * as StreamActions from '../actions/StreamActions'
 import * as constants from '../constants'
-import Peer from 'simple-peer'
+import Peer, { SignalData } from 'simple-peer'
 import forEach from 'lodash/forEach'
 import _debug from 'debug'
 import { play, iceServers } from '../window'
 import { Dispatch, GetState } from '../store'
+import { ClientSocket } from '../socket'
 
 const debug = _debug('peercalls')
 
@@ -15,14 +16,14 @@ export interface Peers {
 }
 
 export interface PeerHandlerOptions {
-  socket: SocketIOClient.Socket
+  socket: ClientSocket
   user: { id: string }
   dispatch: Dispatch
   getState: GetState
 }
 
 class PeerHandler {
-  socket: SocketIOClient.Socket
+  socket: ClientSocket
   user: { id: string }
   dispatch: Dispatch
   getState: GetState
@@ -41,7 +42,7 @@ class PeerHandler {
     peer && peer.destroy()
     dispatch(removePeer(user.id))
   }
-  handleSignal = (signal: unknown) => {
+  handleSignal = (signal: SignalData) => {
     const { socket, user } = this
     debug('peer: %s, signal: %o', user.id, signal)
 
@@ -94,7 +95,7 @@ class PeerHandler {
 }
 
 export interface CreatePeerOptions {
-  socket: SocketIOClient.Socket
+  socket: ClientSocket
   user: { id: string }
   initiator: string
   stream?: MediaStream
diff --git a/src/client/actions/SocketActions.test.ts b/src/client/actions/SocketActions.test.ts
index 735a5b6..6adaee4 100644
--- a/src/client/actions/SocketActions.test.ts
+++ b/src/client/actions/SocketActions.test.ts
@@ -6,12 +6,13 @@ import * as constants from '../constants'
 import Peer from 'simple-peer'
 import { EventEmitter } from 'events'
 import { createStore, Store, GetState } from '../store'
+import { ClientSocket } from '../socket'
 import { Dispatch } from 'redux'
 
 describe('SocketActions', () => {
   const roomName = 'bla'
 
-  let socket: SocketIOClient.Socket
+  let socket: ClientSocket
   let store: Store
   let dispatch: Dispatch
   let getState: GetState
@@ -67,7 +68,7 @@ describe('SocketActions', () => {
       it('should forward signal to peer', () => {
         socket.emit('signal', {
           userId: 'b',
-          data,
+          signal: data,
         })
 
         expect(instances.length).toBe(1)
@@ -77,7 +78,7 @@ describe('SocketActions', () => {
       it('does nothing if no peer', () => {
         socket.emit('signal', {
           userId: 'a',
-          data,
+          signal: data,
         })
 
         expect(instances.length).toBe(1)
diff --git a/src/client/actions/SocketActions.ts b/src/client/actions/SocketActions.ts
index f164465..27913a1 100644
--- a/src/client/actions/SocketActions.ts
+++ b/src/client/actions/SocketActions.ts
@@ -5,11 +5,12 @@ import keyBy from 'lodash/keyBy'
 import _debug from 'debug'
 import { SignalData } from 'simple-peer'
 import { Dispatch, GetState } from '../store'
+import { ClientSocket } from '../socket'
 
 const debug = _debug('peercalls')
 
 export interface SocketHandlerOptions {
-  socket: SocketIOClient.Socket
+  socket: ClientSocket
   roomName: string
   stream?: MediaStream
   dispatch: Dispatch
@@ -27,7 +28,7 @@ export interface UsersOptions {
 }
 
 class SocketHandler {
-  socket: SocketIOClient.Socket
+  socket: ClientSocket
   roomName: string
   stream?: MediaStream
   dispatch: Dispatch
@@ -70,7 +71,7 @@ class SocketHandler {
 }
 
 export interface HandshakeOptions {
-  socket: SocketIOClient.Socket
+  socket: ClientSocket
   roomName: string
   stream?: MediaStream
 }
diff --git a/src/client/socket.ts b/src/client/socket.ts
index 3d6a3e0..4b3a92d 100644
--- a/src/client/socket.ts
+++ b/src/client/socket.ts
@@ -1,3 +1,7 @@
 import SocketIOClient from 'socket.io-client'
 import { baseUrl } from './window'
-export default SocketIOClient('', { path: baseUrl + '/ws' })
+import { TypedEmitterKeys, SocketEvent, TypedEmitter } from '../shared'
+export type ClientSocket = Omit<SocketIOClient.Socket, TypedEmitterKeys> &
+  TypedEmitter<SocketEvent>
+const socket: ClientSocket = SocketIOClient('', { path: baseUrl + '/ws' })
+export default socket
diff --git a/src/server/app.ts b/src/server/app.ts
index f3cba76..7ba1f32 100644
--- a/src/server/app.ts
+++ b/src/server/app.ts
@@ -33,5 +33,6 @@ router.use('/', index)
 app.use(BASE_URL, router)
 
 io.on('connection', socket => handleSocket(socket, io))
+io.sockets.adapter.rooms['test'].sockets
 
 export default server
diff --git a/src/server/socket.test.ts b/src/server/socket.test.ts
index 78c7333..9736e74 100644
--- a/src/server/socket.test.ts
+++ b/src/server/socket.test.ts
@@ -1,6 +1,7 @@
 import { EventEmitter } from 'events'
+import { Socket } from 'socket.io'
+import { TypedIO } from '../shared'
 import handleSocket from './socket'
-import { Socket, Server } from 'socket.io'
 
 describe('server/socket', () => {
   type SocketMock = Socket & {
@@ -12,7 +13,7 @@ describe('server/socket', () => {
   }
 
   let socket: SocketMock
-  let io: Server & {
+  let io: TypedIO  & {
     in: jest.Mock<(room: string) => SocketMock>
     to: jest.Mock<(room: string) => SocketMock>
   }
diff --git a/src/server/socket.ts b/src/server/socket.ts
index 64d7d0e..9305bc4 100644
--- a/src/server/socket.ts
+++ b/src/server/socket.ts
@@ -1,13 +1,11 @@
 'use strict'
 import _debug from 'debug'
 import map from 'lodash/map'
-import { Socket, Server } from 'socket.io'
+import { ServerSocket, TypedIO } from '../shared'
 
 const debug = _debug('peercalls:socket')
 
-type SocketWithRoom = Socket & { room?: string }
-
-export default function handleSocket(socket: SocketWithRoom, io: Server) {
+export default function handleSocket(socket: ServerSocket, io: TypedIO) {
   socket.on('signal', payload => {
     // debug('signal: %s, payload: %o', socket.id, payload)
     io.to(payload.userId).emit('signal', {
diff --git a/src/shared/SocketEvent.ts b/src/shared/SocketEvent.ts
new file mode 100644
index 0000000..a0ae5bb
--- /dev/null
+++ b/src/shared/SocketEvent.ts
@@ -0,0 +1,30 @@
+import { TypedEmitter, TypedEmitterKeys } from './TypedEmitter'
+import { SignalData } from 'simple-peer'
+
+export interface User {
+  id: string
+}
+
+export interface SocketEvent {
+  users: {
+    initiator: string
+    users: User[]
+  }
+  signal: {
+    userId: string
+    // eslint-disable-next-line
+    signal: SignalData
+  }
+  connect: undefined
+  disconnect: undefined
+  ready: string
+}
+
+export type ServerSocket =
+  Omit<SocketIO.Socket, TypedEmitterKeys> &
+  TypedEmitter<SocketEvent> &
+  { room?: string }
+
+export type TypedIO = SocketIO.Server & {
+  to(roomName: string): TypedEmitter<SocketEvent>
+}
diff --git a/src/shared/TypedEmitter.test.ts b/src/shared/TypedEmitter.test.ts
index 11b93c8..4fe0eb6 100644
--- a/src/shared/TypedEmitter.test.ts
+++ b/src/shared/TypedEmitter.test.ts
@@ -38,12 +38,12 @@ describe('TypedEmitter', () => {
   let emitter: TypedEmitter<Events>
   beforeEach(() => {
     emitter = new EventEmitter()
-    emitter.addListener('test1', listener1)
+    emitter.on('test1', listener1)
     emitter.on('test2', listener2)
     emitter.once('test3', listener3)
   })
 
-  describe('addListener & on', () => {
+  describe('on & on', () => {
     it('adds an event emitter', () => {
       emitter.emit('test1', 'value')
       emitter.emit('test2', 3)
diff --git a/src/shared/TypedEmitter.ts b/src/shared/TypedEmitter.ts
index 6dd7acb..c0add9d 100644
--- a/src/shared/TypedEmitter.ts
+++ b/src/shared/TypedEmitter.ts
@@ -1,13 +1,19 @@
-import  { EventEmitter } from 'events'
-
 type Callback<A> = (a: A) => void
 
 // eslint-disable-next-line
 type Events = Record<string | symbol, any>
 
-export interface TypedEmitter<E extends Events>
-extends EventEmitter {
-  addListener<K extends keyof E>(t: K, callback: Callback<E[K]>): this
+export type TypedEmitterKeys =
+  'removeListener' |
+  'on' |
+  'once' |
+  'off' |
+  'emit'
+
+// Some methods might be missing and we do not extend EventEmitter because
+// SocketIOClient.Socket does not inherit from EventEmitter, and the method
+// signatures differ slightly.
+export interface TypedEmitter<E extends Events> {
   removeListener<K extends keyof E>(t: K, callback: Callback<E[K]>): this
 
   on<K extends keyof E>(t: K, callback: Callback<E[K]>): this
@@ -15,5 +21,5 @@ extends EventEmitter {
 
   off<K extends keyof E>(t: K, callback: Callback<E[K]>): this
 
-  emit<K extends keyof E>(t: K, value: E[K]): boolean
+  emit<K extends keyof E>(t: K, value: E[K]): void
 }
diff --git a/src/shared/index.ts b/src/shared/index.ts
new file mode 100644
index 0000000..231f83e
--- /dev/null
+++ b/src/shared/index.ts
@@ -0,0 +1,2 @@
+export * from './SocketEvent'
+export * from './TypedEmitter'