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Bun

DEVOPS
Velocity3.8

Fast all-in-one JavaScript runtime and toolkit

bun.sh ↗

Bun is rewriting its core from Zig to Rust while shipping built-in APIs at a monthly clip.

runtimenodejs-compatibilityrust-rewriteperformancebuilt-in-apisdeveloper-tools
◆Current state
Bun ships a substantial point release roughly monthly, each widening Node.js compatibility and folding more capability into the runtime itself — image processing, Markdown parsing, cron, archives, a headless WebView, HTTP/2 and HTTP/3 clients. Performance work is constant, with double-digit speedups landing release over release. In July the team disclosed it is rewriting Bun's implementation from Zig to Rust.
◆Where it's heading
Two arcs run in parallel: keep absorbing what developers reach for third-party packages to do, so the runtime is batteries-included, and re-lay the foundation in Rust for a larger contributor pool and easier maintenance. The near-term feature cadence has not slowed, which suggests the rewrite is incremental rather than a hard fork.
◆Prediction
Expect continued monthly 1.3.x releases centered on Node compatibility and built-in APIs, with the Rust migration surfaced through engineering write-ups before it changes anything user-facing.

◆Recent moves

  1. 1d ago

    Rewriting Bun in Rust

    ⚡ SPARK

    A ground-up rewrite of Bun from Zig to Rust — the most consequential architectural decision in the project's history, and a bet that Rust's ecosystem and contributor base outweigh the cost of re-implementation.

    View source ↗
  2. 1mo ago

    Bun 1.3.14 adds built-in image processing and HTTP/3

    A dense release: a built-in Bun.Image API, 7x faster warm installs, experimental HTTP/2 and HTTP/3 fetch clients, and QUIC in Bun.serve. Continues the pattern of absorbing more into the runtime.

    View source ↗
  3. 2mo ago

    Bun 1.3.13 adds a parallel test runner and 17x-leaner installs

    The test runner gains --parallel, --isolate, --shard, and --changed, and installs stream tarballs using 17x less memory. Tooling and efficiency, squarely incremental.

    View source ↗
  4. 3mo ago

    Bun 1.3.12 adds headless WebView automation and in-process cron

    Adds a Bun.WebView headless browser, an in-process cron scheduler, and terminal Markdown rendering. More built-ins folded into the runtime.

    View source ↗
  5. 3mo ago

    Bun 1.3.11 adds OS-level cron and ANSI-aware string tools

    OS-level Bun.cron, ANSI/grapheme-aware string slicing, and a batch of Windows and Node-compat fixes. Steady maintenance and small primitives.

    View source ↗
  6. 4mo ago

    Bun 1.3.10 adds a native REPL and browser-target compile

    A native REPL, --compile --target=browser for self-contained HTML, standard ES decorators, and Windows ARM64 support, plus large JS-engine speedups. Broadening reach and platforms.

    View source ↗