Vercel "FUNCTION_INVOCATION_TIMEOUT"

What it means

A server function took longer than your Vercel plan allows, so Vercel stopped it and returned a 504.

Why AI tools cause it

• Waiting for a long AI response to finish before replying.
• Doing several slow jobs one after another (scraping, image generation, big database queries).
• A request that never returns, such as a database call that hangs or a missing return in a route.

The fix

1. Stream AI responses instead of waiting for the whole answer. The user sees text straight away and the function stays responsive.
2. Run independent slow calls at the same time with Promise.all.
3. If a job really is long, raise the function's maximum duration within your plan's limit (export const maxDuration = ... in Next.js), or move it to a background job and let the page check back.
4. Add timeouts to outside calls so a hung request fails fast with a clear error.

Paste this into your AI

This Vercel function times out with FUNCTION_INVOCATION_TIMEOUT. Find what's slow, stream any AI responses, run independent calls in parallel, add timeouts to external requests, and tell me if this job should be moved to a background task.

Still broken?

Check Vercel's function logs for the request. If it times out even on tiny inputs, something is hanging rather than slow.