A third runtime, Node-compatible
After Node.js (2009) and Deno (2020), a third contender: Bun, founded by Jarred Sumner at Oven Labs (2022). Version 1.0 is released on 8 September 2023. MIT licence.
Bun is written in Zig (emerging systems language, C-compatible with optional memory safety) and uses JavaScriptCore (Safari’s engine) instead of V8 (Chrome/Node/Deno). Choices explaining part of the performance.
Three tools in one binary
Bun is deliberately all-in-one:
- Runtime — executes JS/TS, Node.js API-compatible (filesystem, HTTP, buffer, stream, timer, etc.)
- Package manager —
bun installcompatible with package.json and node_modules, significantly faster than npm/yarn/pnpm - Bundler —
bun buildalternative to Webpack/Vite for simple tasks - Test runner —
bun testwith Jest-compatible API bun x— temporary binary executor, npx alternative- Built-in file server with hot reload
Performance
Benchmarks published by Oven and third parties:
- bun install 10-30x faster than npm
- bun run startup 3-4x faster than node
- bun build comparable to esbuild
- Built-in HTTP server throughput 2-3x Node.js native
Performance is genuine for pure workloads; advantage reduces when the bottleneck is external I/O (network, disk).
Node.js compatibility
Bun aims at Node.js drop-in replacement where possible. API compatibility is documented and tracked; as of 2023-2024 most npm libraries run unchanged. Some particular cases (native addons, internal Node APIs) remain not fully supported.
Bun SQLite built-in
Bun includes bun:sqlite — built-in SQLite binding, as fast as the original C. Useful for scripts, prototyping, edge computing.
Adoption
As of 2023-2024 Bun is still early-adopter:
- Fast package installer — partial use for npm install in CI
- Scripting and CLI utilities
- Edge computing — bun run on Cloudflare Workers (via custom runtime)
Production use of core applications requires caution due to imperfect Node.js compatibility; many teams use it as secondary tooling rather than primary runtime.
In the Italian context
Limited, experimental presence in Italian startups and freelance teams.
References: Bun 1.0 (8 September 2023). Jarred Sumner, Oven Labs (founded 2022). MIT licence. Zig language. JavaScriptCore engine. All-in-one: runtime + bundler + package manager + test runner.