timeout(ms)

Guarantee a request gets an answer: if the handler does not respond within ms, reply 504.

Use case

A slow dependency (a stuck database query, an unresponsive upstream) can leave a request hanging forever, tying up the client and consuming server resources. A response deadline turns "hangs indefinitely" into a predictable 504 Gateway Timeout, so clients can retry or fail fast.

How it works

It starts a timer when the request enters. It wraps res.json, res.text, and res.html so that sending a response clears the timer. If the timer fires first (no response within ms), it replies 504 Gateway Timeout. The argument is the deadline in milliseconds.

Configuration

The single argument is the timeout in milliseconds.

Example

Pair a generous global timeout with a tighter per-route one for endpoints you know should be fast.

Notes

A timeout protects the client's experience; it does not cancel the slow work already running server-side. Use it together with sensible timeouts on your own outbound calls (database, fetch) so the underlying operation is bounded too, not just the response.

Next: errorHandler.