Bun was created by Jarred Sumner and publicly launched in July 2022. Oven, the company behind Bun, is based in San Francisco and raised $7 million in seed funding. Bun 1.0 was officially released in September 2023.
Unlike Node.js and Deno, which use V8, Bun is built on Apple’s JavaScriptCore engine (the same one powering Safari). It’s written in Zig, a low-level language designed for performance. The result is a runtime that’s dramatically faster at many tasks — startup times are up to 4x faster than Node.js, and package installs can be 25x faster than npm.
Bun isn’t just a runtime. It’s a package manager that’s compatible with npm’s package.json and node_modules. It’s a bundler that can replace Webpack or esbuild for many use cases. It’s a test runner with Jest-compatible syntax. And it’s a transpiler that handles TypeScript and JSX natively without any configuration.
The goal is to replace multiple tools with a single fast binary. Instead of needing Node.js plus npm plus a bundler plus a test runner plus a transpiler, you just need Bun. It implements most of Node.js’s APIs, so many existing npm packages work without changes.
Bun has over 74,000 GitHub stars, making it one of the fastest-growing developer tools. It’s still maturing — some Node.js APIs aren’t fully implemented yet — but the speed improvements are real and measurable. Companies are starting to adopt it for build scripts and development workflows where speed matters most.
