Bun 73,307 , written in Zig by Jarred Sumner and released as 1.0 in September 2023, is a JavaScript runtime, bundler, test runner and package manager in one binary. bun install also works alone, as a faster npm 2,036 install for a project that still runs on Node.js 2,131 , which is how this section uses Bun 1.4.2.