Vercel·Fixdeployintermediate

Vercel API Route Works Locally but Times Out in Production

Quick Answer

How do I fix Vercel API Route Works Locally but Times Out in Production?

Vercel free tier has a 10-second function timeout. Long-running operations hit this limit. Start with "Optimize or move long operations" before making broader code changes.

Fix signals

What this answers: Why vercel api route works locally but times out in production happens and what to change first.
Fastest move: Optimize or move long operations
Use this page if: 504 Gateway Timeout

If this keeps happening

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Quick Fix Summary

Most likely cause	Vercel free tier has a 10-second function timeout. Long-running operations hit this limit.
Fastest fix	Optimize or move long operations
Use this page if	504 Gateway Timeout

Exact errors people search for

If one of these matches what you are seeing, you are likely on the right fix page.

Vercel API route works locally but times out in production
504 Gateway Timeout appears on the deployed API route
Long-running function keeps failing only on Vercel

You're in the right place if...

!504 Gateway Timeout
!API routes return timeout error
!Functions work locally but timeout on Vercel

Why this happens

Vercel free tier has a 10-second function timeout. Long-running operations hit this limit.

Fix

Optimize or move long operations

Solutions by priority:

1. Move long operations to background jobs
2. Use streaming responses instead of waiting
3. Switch to Railway for long-running processes
4. Add vercel.json to increase timeout (Pro only):
{
  "functions": {
    "api/long-task.ts": {
      "maxDuration": 60
    }
  }
}

Prevent this next time

Design API routes to complete in under 10 seconds. Use streaming for AI responses. Use queues for heavy processing.