Bun Runtime on Vercel Now Supports 5GB Packages and 30-Minute Functions

Vercel Functions using the Bun runtime now support large functions (up to 5GB uncompressed) and extended max duration (up to 30 minutes, or 1,800 seconds) — two betas that previously ran on Node.js and Python only.

What changed. The standard 250MB package size limit jumps to 5GB for large functions. The GA ceiling of 800 seconds (13.3 minutes) extends to 1,800 seconds for Pro and Enterprise teams. Both features require Fluid Compute to be enabled. New projects get the large functions beta automatically; existing projects need to set VERCEL_SUPPORT_LARGE_FUNCTIONS=1 and redeploy. Durations above 800 seconds are set per-function via maxDuration in vercel.json.

Why a builder cares. Bun on Vercel was previously limited to small, short-lived serverless functions — now you can deploy heavy workloads like video processing, data pipelines, or full Bun HTTP servers that run for up to half an hour. The 5GB budget also means large Node.js migrations and heavy dependency graphs no longer hit the ceiling.

Caveats. These betas are unavailable on projects using Secure Compute or Static IPs.