Vercel launches Bun runtime for Functions (Public Beta)

Key update

Vercel added the Bun runtime to Vercel Functions as a public beta, allowing projects to opt into Bun by setting bunVersion in vercel.json and run serverless functions natively on Bun instead of Node.js. The initial platform support explicitly mentions Next.js, Hono, Express and Nitro, and Vercel says Bun deployments integrate with their logging and observability. Vercel’s internal benchmarks show roughly a 28% average latency reduction for CPU‑bound Next.js server‑side rendering workloads when using Bun versus Node.js.

Why it matters

This is the most practical deployment milestone for Bun so far: first‑class platform support on a major serverless host removes a key adoption blocker and makes it straightforward to validate Bun under real traffic patterns without custom images or complex hosting workarounds. For teams, that means an easy, low-friction path to measure real-world gains (faster cold starts, lower SSR latency, and less overhead when running TypeScript) while keeping Vercel’s operational tooling. It is not an automatic drop‑in for all workloads—differences remain around native modules, some Node APIs and ecosystem edge cases—so treat the beta as an evaluation path: pin the Bun runtime version, update build/dev scripts to use Bun where recommended, run end‑to‑end correctness and performance tests in staging, and validate observability and metrics before migrating production traffic. If your workload is CPU‑bound (SSR, image processing, heavy JSON/crypto), expect measurable latency and cost improvements; if you rely on obscure native node: APIs or binary N‑API modules, plan compatibility testing and fallback options.

Source

• Source