SSE vs WebSockets vs Polling Comparison
Compare SSE (unidirectional push), WebSockets (bidirectional), and polling across use case fit and complexity.
WebSockets: Bidirectional Persistent Connection
WebSockets establish a persistent TCP connection between client and server. Both sides can send messages at any time, making WebSockets ideal for truly interactive real-time communication: chat applications, collaborative document editing, multiplayer games, and live cursors. The connection stays open until explicitly closed by either party.
Server-Sent Events: Unidirectional Push
SSE (Server-Sent Events) uses a regular HTTP connection where the server streams data to the client as a series of events. The connection is one-directional: only the server sends data. The client cannot send messages back through the SSE connection — it makes separate HTTP requests for that. SSE is implemented via the EventSource browser API.
All lessons in this course
- SSE vs WebSockets vs Polling Comparison
- Consuming SSE Streams in React with EventSource
- Long Polling Pattern and Reconnection Logic
- Building a Real-Time Notification Feed