Push live updates to a browser with a WebSocket instead of polling

My dashboard polls every couple of seconds and it still feels a beat behind.

Intermediate to advancedRead 6 minDoing: an afternoon, with your project open7 steps

▶ Start

What you'll have at the end

A browser tab holding one WebSocket connection that receives pushed messages with no polling

Before you start

You need

A running application with a route the browser dashboard currently polls on a timer, and a second route that changes the value being polled.

Not covered

Spreading that same registry of connections across more than one running server process, which needs a shared broadcast layer this recipe does not build, is not covered here.

Leans on

FastAPI Cheat Sheetthe accept, disconnect and send-message rows this whole recipe is built from.
WebSocket Implementation Cheat Sheetthe heartbeat interval, backoff and jitter, and broadcast patterns the later steps wire in.

7 steps

Where to go next

One shared dependency instead of a check copied into every route

when the connection itself needs a login check before it opens, reuse that same shared dependency instead of copying an auth check into this route too.

Checked 18 Aug 2026

Part of the FastAPI cookbook