Bun runtime now supports large functions and extended max duration
Vercel Functions now supports larger Bun runtime packages up to 5GB and extended execution durations up to 30 minutes, previously limited to Node.js and Python.
The Bun runtime on Vercel Functions has introduced support for larger package sizes, increasing the standard 250MB limit to 5GB uncompressed. This change applies to both new and existing projects, with new projects automatically enrolled in the beta. Existing projects created before July 2026 must opt in by setting the environment variable VERCEL_SUPPORT_LARGE_FUNCTIONS=1 and redeploying to access the expanded capacity.
Extended maximum duration for Bun functions has also been raised from 800 seconds to 1,800 seconds for Pro and Enterprise teams. This adjustment allows longer-running processes, though it requires Fluid compute to be enabled. The extended duration is configured per function in vercel.json rather than as a project-wide default, providing more granular control over execution limits.
Both features remain in beta and are currently unavailable for projects using Secure Compute or Static IPs. Users must ensure their projects meet these requirements to utilize the new capabilities. The changes aim to broaden the scope of applications that can run on Vercel Functions, particularly those with larger dependencies or extended processing needs.
To implement these updates, developers should review the official documentation for large functions and extended duration features. The adjustments reflect Vercel’s ongoing expansion of runtime capabilities beyond Node.js and Python, enhancing flexibility for Bun-based deployments.