Bun runtime now supports large functions and extended max duration

The Bun runtime on Vercel Functions now supports larger package sizes up to 5GB uncompressed and extended max duration for up to 30 minutes, two betas that previously ran on Node.js and Python only.

Large functions raise the standard 250MB package size limit to 5GB, and extended max duration raises the generally available 800-second ceiling to 1800 seconds for Pro and Enterprise teams. Both features require Fluid compute to be enabled. New projects are enrolled in the large functions beta automatically, while existing projects created before July 2026 opt in by adding VERCEL_SUPPORT_LARGE_FUNCTIONS=1 as an environment variable in your project settings, then redeploying. Durations above 800 seconds are set per function in vercel.json rather than as a project-level default:

The server.ts entry point serves the long-running route with Bun:

During the beta, these features are unavailable on projects using Secure Compute or Static IPs.

Read the large functions and extended max duration documentation.