Long Polling and the Evolution Toward Streaming
Understand long polling as a bridge technique between traditional HTTP and modern live data transports, when it still matters, and how it compares to WebSockets and SSE.
Why Long Polling Exists
Before WebSockets and SSE were widely supported, developers needed a way to push data to clients over plain HTTP. Long polling filled that gap.
With long polling, the client makes a request and the server holds it open until new data is available, instead of replying immediately.
Short Polling vs Long Polling
Short polling hammers the server on a fixed interval, wasting requests when nothing changed.
- Short polling: request, immediate empty reply, wait, repeat.
- Long polling: request, server waits, replies only when data arrives.
Long polling cuts the volume of empty responses dramatically.
All lessons in this course
- Live Data vs. Traditional HTTP
- WebSockets for Bidirectional Flow
- Server-Sent Events (SSE) for Unidirectional Push
- Long Polling and the Evolution Toward Streaming