Bun (software)

Bun
Original authorJarred Sumner
DeveloperAnthropic
Initial releaseSeptember 14, 2021 (2021-09-14)
Stable release
1.3.5  / 17 December 2025 (17 December 2025)
Written inZig, C++ (JSC bindings), C (WebSocket bindings), TypeScript, JavaScript
Operating systemLinux, macOS, Windows
TypeRuntime environment
LicenseMIT license
Websitebun.com
Repositorygithub.com/oven-sh/bun

Bun is a JavaScript runtime, package manager and test runner designed as a drop-in replacement for Node.js. Bun uses Safari's JavaScriptCore as its JavaScript engine , unlike Node.js and Deno, which run on the V8 engine used by the Chromium project. It is currently owned by Anthropic PBC, having formerly been its own company, Oven.