Bun v1.3.10 Released With Rewritten REPL

The rewritten REPL is built from the ground up in Zig, a low-level programming language, replacing a third-party npm package. This change contributes to Bun's core design goal of speed by eliminating layers of abstraction and making direct system calls to the operating system. The new REPL is not just faster but also includes features like top-level await, persistent history, and syntax highlighting. Bun was created by Jarred Sumner and is designed as an all-in-one toolkit to be a faster, drop-in replacement for Node.js. It uses Apple's JavaScriptCore engine, unlike Node.js and Deno which use Google's V8, contributing to quicker startup times and reduced memory usage. In late 2025, the project was acquired by Anthropic to provide long-term stability and to use Bun for its AI coding tools. For full-stack developers using React or Next.js, Bun's primary advantage is its integrated toolchain; it combines a runtime, package manager, bundler, and test runner into a single executable. This consolidation means fewer dependencies and configuration files, simplifying project setup and maintenance compared to the traditional Node.js ecosystem which requires separate tools like npm, Webpack, and Jest. The performance gains are tangible during development. Package installation with `bun install` can be 10-30 times faster than npm, significantly speeding up project initialization and dependency management. When working on Next.js applications, this translates to faster dev server startups and near-instant hot reloads, creating a more fluid and efficient coding experience. Bun's built-in bundler competes with tools like Vite and Webpack by offering high speeds without complex configuration. It provides out-of-the-box support for TypeScript and JSX, which means developers can run `.ts` and `.tsx` files directly without a separate transpilation step, further streamlining the development workflow for modern web applications. Beyond the frontend, Bun includes native, highly-optimized APIs for backend tasks. For instance, `Bun.serve()` can handle significantly more HTTP requests per second than Node.js with Express. It also offers built-in clients for SQLite and other databases, which can be faster than their Node.js package counterparts, reducing the need for external dependencies when building APIs and connecting to databases. Looking ahead, Bun aims to be fully compatible with Node.js, allowing developers to adopt its tools incrementally in existing projects. The roadmap includes further enhancements to its all-in-one toolkit, with the goal of replacing the fragmented toolchains common in JavaScript development today.