Real-Time Chat Backend API with WebSockets, Persistence, and Presence Tracking

Create and construct a WebSockets-based scalable backend API for a real-time chat application. The system should support low-latency bidirectional communication between clients and servers.

Conditions:

1. WebSocket Interaction:
   • Create and maintain long-term WebSocket connections.
   • Manage the broadcasting of messages (1:1 and group chats).
   • Make that the connection lifecycle (connect, detach, reconnect) is managed effectively.
2. Handling and Storing Messages:
   • Save chat messages with timestamps, sender IDs, and message statuses in a database.
   • Provide pagination support for message history retrieval.
   • Make sure the data is reliable and consistent.
3. Monitoring User Presence:
   • Monitor and instantly update a user’s online and offline status.
   • Notify the appropriate users of changes in your presence.
   • Address edge circumstances such as sudden disconnections.
4. Performance and Scalability:
   • Design with horizontal scalability in mind (e.g., distributed systems, load balancing).
   • Aim for low latency and high concurrency.
5. Reliability & Security:
   • Put authentication into practice (e.g., session-based or JWT).
   • Make sure that messages are transmitted securely.
   • Retries and errors should be handled politely.
6. Technology Stack (preferred but not required):
   • Indicate your desired backend framework or language (e.g., Node.js, Python, .NET).
   • Make use of the proper databases (Redis for presence, NoSQL for chat logs, etc.).

Anticipated Results:

• Overview of API architecture
• WebSocket events and important endpoints
• Schema design and data models
• Examples of implementation snippets
• Best practices for scalability and deployment