SSE vs webSocket vs Long Polling

I was learning SSE today, and kinda confused about the SSE with other server-client communication methods, so here is short summary of the learning outcome.

This post is a shallow comparison between the normal http requests, short polling, long polling, webSocket, and SSE.

• Communication Method

  • HTTP Requests: One-way request/response.

  • Short Polling: One-way request/response.

  • Long Polling: One-way request/response.

  • WebSocket: Full-duplex, bidirectional communication.

  • SSE: One-way communication (server to client).

• Connection Persistence

  • HTTP Requests: A new connection is established for every request.

  • Short Polling: Each request closes after completion.

  • Long Polling: Each request closes after completion.

  • WebSocket: Persistent connection until explicitly closed.

  • SSE: Persistent connection until explicitly closed.

• Real-Time Capability

  • HTTP Requests: Low (requires new requests after each response).

  • Short Polling: Medium (depends on polling frequency).

  • Long Polling: Medium-High (server can push data proactively).

  • WebSocket: Very high (minimal latency).

  • SSE: Medium-High (server can push data proactively).

• Performance

  • HTTP Requests: High overhead (frequent connection setup).

  • Short Polling: Medium (frequent requests).

  • Long Polling: Lower (reduces unnecessary requests).

  • WebSocket: Optimal (single connection, low overhead).

  • SSE: Efficient (single connection, low overhead).

• Use Cases

  • HTTP Requests: Static data fetching or short-lived interactions.

  • Short Polling: Scenarios with infrequent data updates (e.g., weather updates).

  • Long Polling: Applications needing real-time updates (e.g., chat systems).

  • WebSocket: High-frequency, real-time bidirectional data exchange.

  • SSE: One-way real-time data streams (e.g., notifications, live feeds).