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bun

Incredibly fast JavaScript runtime, bundler, test runner, and package manager – all in one

GitHubbun.com
bunbundlerjavascriptjavascriptcorejsxnodejsnpmreactrustrust-langtranspilertypescript
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17,056commits
915contributors
20languages

Tech stack & purpose

Bun is an all-in-one JavaScript runtime, bundler, test runner, and package manager designed for speed, built primarily in Rust with C++ bindings for JavaScriptCore integration. The project includes extensive benchmarks comparing Bun's performance against other tools like esbuild, Webpack, Jest, and Vitest across bundling, HTTP serving, testing, file uploads, WebSockets, and other workloads. The repository contains the core implementation organized as a Rust Cargo workspace of approximately 200 crates covering the runtime, CLI, parser, transpiler, and built-in modules, along with comprehensive test suites organized by functionality (Bun-specific APIs, Node.js compatibility, Web APIs, CLI commands, bundler, and integration tests).

Community & reference links

Languages

Rust
65.0%
C++
20.9%
TypeScript
8.9%
C
2.7%
JavaScript
1.7%
Shell
0.3%
Python
0.1%
PowerShell
0.1%
Objective-C
0.1%
CSS
0.1%
Perl
0.0%
HTML
0.0%
Dockerfile
0.0%
HCL
0.0%
Ruby
0.0%
Linker Script
0.0%
Nix
0.0%
Svelte
0.0%
Makefile
0.0%
MDX
0.0%

Contributors (top 30 of 915)