Getting Timeouts When Deploying on Vercel

Issue

Streaming with the AI SDK works in my local development environment. However, when I'm deploying to Vercel, longer responses get chopped off in the UI and I'm seeing timeouts in the Vercel logs or I'm seeing the error: Uncaught (in promise) Error: Connection closed.

Solution

With Vercel's Fluid Compute, the default function duration is now 5 minutes (300 seconds) across all plans. This should be sufficient for most streaming applications.

If you need to extend the timeout for longer-running processes, you can increase the maxDuration setting:

Next.js (App Router)

Add the following to your route file or the page you are calling your Server Action from:

export const maxDuration = 600;

Other Frameworks

For other frameworks, you can set timeouts in your vercel.json file:

{
  "functions": {
    "api/chat/route.ts": {
      "maxDuration": 600
    }
  }
}

Maximum Duration Limits

The maximum duration you can set depends on your Vercel plan:

• Hobby: Up to 300 seconds (5 minutes)
• Pro: Up to 800 seconds (~13 minutes)
• Enterprise: Up to 800 seconds (~13 minutes)

Learn more

• Fluid Compute Default Settings
• Configuring Maximum Duration for Vercel Functions