Real-time Chat Server with Ktor WebSockets

Project roadmap

1. 01

   Build single-instance WebSocket server

   ~2.5h

   Implement Ktor WebSocket routes for joining rooms and broadcasting messages to connected sessions.

2. 02

   Add room and user management

   ~2h

   Track active rooms and users in-memory using thread-safe coroutine structures.

3. 03

   Integrate Redis pub/sub

   ~2.5h

   Publish incoming messages to Redis channels so multiple server instances stay in sync.

4. 04

   Handle reconnects and backpressure

   ~2h

   Add heartbeat pings, reconnect logic, and bounded channels to avoid overwhelming slow clients.

5. 05

   Load test and scale

   ~2h

   Run multiple server instances behind a reverse proxy and verify cross-instance message delivery under load.

Resources

• DocsKotlin Docs