Chatroom

Backend for a real-time chat room app in a highly scalable architecture.

System architecture

Features

• Real-time chatting using websockets.

• Services are stateless and can be horizontally scaled.

  • room: creates rooms (public/protected) and handles messages.
  • subscriber: maintains Kafka subscriber topics for each room in a Redis cluster.

• Traefik for efficient HTTP reverse proxying and load balancing

• gRPC for low-latency and high-throughput inter-service communication.

  • with retry (Exponential backoff with jitter), timeout, and circuit breaker.

• Graceful shutdown.

• Observability using Prometheus + Grafana for service monitoring and OpenTelemetry + Jaeger for distributed tracing.

• Pub/Sub using Kafka with partitioning for parallel processing.

• Persist messages and rooms in Cassandra, A highly available and scalable NoSQL Database with tunable consistency.

• Protect the create room API with distributed rate limiting using the Token-Bucket Algorithm with Redis.

• Broadcasting seen, typing, joining, and leaving events to all room members.