diff --git a/backend/shared/interfaces/ChatRoom.ts b/backend/shared/interfaces/ChatRoom.ts
deleted file mode 100644
index 89230b7c..00000000
--- a/backend/shared/interfaces/ChatRoom.ts
+++ /dev/null
@@ -1,4 +0,0 @@
-export class ChatRoom {
-  roomName: string;
-  userIdList: number[];
-}
\ No newline at end of file
diff --git a/backend/shared/interfaces/UserWebsockets.ts b/backend/shared/interfaces/UserWebsockets.ts
new file mode 100644
index 00000000..0e141bab
--- /dev/null
+++ b/backend/shared/interfaces/UserWebsockets.ts
@@ -0,0 +1,4 @@
+export class UsersWebsockets {
+  userId: number;
+  socketId: string;
+}
diff --git a/backend/src/chat/chat.gateway.ts b/backend/src/chat/chat.gateway.ts
index 7209dc68..8ea29b55 100644
--- a/backend/src/chat/chat.gateway.ts
+++ b/backend/src/chat/chat.gateway.ts
@@ -6,6 +6,9 @@ import {
 import {
   ConnectedSocket,
   MessageBody,
+  OnGatewayConnection,
+  OnGatewayDisconnect,
+  OnGatewayInit,
   SubscribeMessage,
   WebSocketGateway,
   WebSocketServer,
@@ -40,7 +43,7 @@ async function passwordCompare(
   transport: ['websocket'],
   cors: '*/*',
 })
-export class ChatGateway {
+export class ChatGateway implements OnGatewayConnection, OnGatewayDisconnect {
   private channelLobby = 'channelLobby';
   constructor(
     private readonly chatService: ChatService,
@@ -49,7 +52,27 @@ export class ChatGateway {
 
   @WebSocketServer()
   server: Server;
+  async handleConnection(@ConnectedSocket() client: Socket) {
+    const user = await this.chatService.getUserFromSocket(client);
 
+    const isRegistered = ChatService.userWebsockets.find(
+      (element) => element.userId === user.id,
+    );
+
+    if (!isRegistered) {
+      const newWebsocket = { userId: user.id, socketId: client.id };
+      ChatService.userWebsockets = [
+        ...ChatService.userWebsockets,
+        newWebsocket,
+      ];
+    }
+  }
+
+  handleDisconnect(@ConnectedSocket() client: Socket) {
+    ChatService.userWebsockets = ChatService.userWebsockets.filter(
+      (websocket) => websocket.socketId !== client.id,
+    );
+  }
   /* JOIN CHANNEL LOBBY */
   @UseGuards(JwtWsGuard)
   @SubscribeMessage(ROUTES_BASE.CHAT.JOIN_CHANNEL_LOBBY_REQUEST)
@@ -174,6 +197,20 @@ export class ChatGateway {
 
     await client.join(newDMRoom.roomName);
 
+    const receiverSocketId = this.chatService.getUserIdWebsocket(friendId);
+
+    if (receiverSocketId) {
+      /** Retrieve receiver's socket with the socket ID
+       * https://stackoverflow.com/questions/67361211/socket-io-4-0-1-get-socket-by-id
+       */
+
+      const receiverSocket = this.server.sockets.sockets.get(
+        receiverSocketId.socketId,
+      );
+
+      await receiverSocket.join(newDMRoom.roomName);
+    }
+
     this.server
       .in(newDMRoom.roomName)
       .emit(ROUTES_BASE.CHAT.CONFIRM_DM_CHANNEL_CREATION, {
diff --git a/backend/src/chat/chat.service.ts b/backend/src/chat/chat.service.ts
index aa1d78d8..aff8d50f 100644
--- a/backend/src/chat/chat.service.ts
+++ b/backend/src/chat/chat.service.ts
@@ -1,6 +1,6 @@
 import { BadRequestException, Injectable } from '@nestjs/common';
 import { AuthService } from '../auth/auth.service';
-import { Socket } from 'socket.io';
+import { Server, Socket } from 'socket.io';
 import { parse } from 'cookie';
 import { WsException } from '@nestjs/websockets';
 import { InjectRepository } from '@nestjs/typeorm';
@@ -10,7 +10,7 @@ import { User } from 'src/user/user.entity';
 import Room from './room.entity';
 import { UsersService } from 'src/user/user.service';
 import { v4 as uuidv4 } from 'uuid';
-import { ChatRoom } from 'shared/interfaces/ChatRoom';
+import { UsersWebsockets } from 'shared/interfaces/UserWebsockets';
 import ChannelData from 'shared/interfaces/ChannelData';
 @Injectable()
 export class ChatService {
@@ -24,7 +24,7 @@ export class ChatService {
     private usersRepository: Repository<User>,
     private userService: UsersService,
   ) {}
-  private static chatRoomList: ChatRoom[] = [];
+  public static userWebsockets: UsersWebsockets[] = [];
 
   public async getAllPublicRooms(): Promise<ChannelData[]> {
     return this.roomsRepository
@@ -246,18 +246,9 @@ export class ChatService {
     return user;
   }
 
-  //Unused fct
-  removeUserConnectedToRooms(roomName: string, userId): number[] {
-    const chatRoomIndex = ChatService.chatRoomList.findIndex(
-      (chatRoom) => chatRoom.roomName == roomName,
+  getUserIdWebsocket(receiverId: number): UsersWebsockets | undefined {
+    return ChatService.userWebsockets.find(
+      (receiver) => receiver.userId === receiverId,
     );
-    if (ChatService.chatRoomList[chatRoomIndex].userIdList.includes(userId)) {
-      ChatService.chatRoomList[chatRoomIndex].userIdList =
-        ChatService.chatRoomList[chatRoomIndex].userIdList.filter(
-          (id) => id !== userId,
-        );
-    }
-    return ChatService.chatRoomList[chatRoomIndex].userIdList;
   }
-  /** END ChatRoomConnectedUsers methods */
 }