signal insight

Vercel Functions now support Bun 1.4, a Rust rewrite of the runtime

On August 20, 2026, Vercel made Bun 1.4 available in Vercel Functions; Bun 1.4 is a complete rewrite from Zig to Rust with improved Node.js compatibility and bug fixes.

Published Aug 20, 2026 Updated Aug 21, 2026 1 sources

VercelVercel Functionsinfrastructurefeature updatemedium impact

infrastructurejavascript-runtimeserverlessfeature update

Impact: medium
Confidence: 88%
Change type: feature update
First seen: Aug 20, 2026
Last updated: Aug 21, 2026
Audience: developers
Status: Ready

Summary

On August 20, 2026, Vercel made Bun 1.4 available in Vercel Functions; Bun 1.4 is a complete rewrite from Zig to Rust with improved Node.js compatibility and bug fixes.

What changed

Vercel Functions added support for the Bun 1.4 runtime.

Why it matters

Offering Bun 1.4 gives Vercel developers a faster JavaScript runtime option with better Node.js compatibility, widening runtime choice on the platform.

Evidence excerpt

A complete rewrite of Bun from Zig to Rust, with many improvements to Node.js compatibility and bug fixes.

Sources

vercel.com