?? Websockets or SSE: Which One to Choose for Your Notification System?

When building real-time notification systems, a common question arises: Should I use Websockets or SSE (Server-Sent Events)?

Both technologies have their strengths, but they also come with unique challenges—especially when it comes to retry mechanisms. Let’s dive in!

?? Websockets: Power and Flexibility

• Bidirectional Communication: Enables simultaneous data flow between client and server.
• Use Cases: Chats, multiplayer systems, or applications needing frequent client-to-server data flow.
• Retry: Websockets require manual management for reconnection, but tools like RxJS or WebSocket helper libraries can simplify implementing retry strategies, including exponential backoff.
• Scalability: Demands more infrastructure (e.g., load balancers) but offers robust flexibility for a wide range of use cases.

?? SSE: Simplicity with Limitations

• Unidirectional Communication: Data flows only from the server to the client.
• Use Cases: Real-time notifications, continuous updates (e.g., news feeds or stock prices).
• Retry: SSE natively supports automatic reconnection. The client retries based on the Retry-After header, but managing complex flows or frequent network failures can be trickier compared to Websockets.
• Simplicity: A great choice when the client only needs to "listen" to the server.

?? Retry: A Critical Factor

Handling reconnections is vital for real-time systems because network failures are inevitable. Choosing the right technology means evaluating:

• How critical is real-time delivery?
• What behavior is expected during a failure?
• How many users need to be supported concurrently?

???? In Summary

• For bidirectional communication and precise retry control, Websockets are the better choice.
• For simple, unidirectional notifications, SSE is lightweight and efficient, though handling repeated failures might be more challenging.

?? The key lies in understanding your project's requirements and the user experience you want to deliver.

?? What about you? How have you tackled real-time notifications? Have you implemented retry strategies? Share your experiences in the comments! ??