Speed and unified tooling
The Bun 1.4.2 release from September 2026 uses a Rust rewrite from August 2026. Bun handles 48,243 requests per second, beating Node 26.7.0’s 25,181. Cold starts in Bun take 8 to 15 milliseconds, whereas Node 24 takes 40 to 120 milliseconds. Installing a fresh React application takes Bun 2 to 3 seconds, but npm takes 30 to 45 seconds. Bun provides a bundler, test runner, package manager, and SQLite driver in one 40 MB binary. I find the all-in-one toolchain useful for new microservices. This single binary uses JavaScriptCore, the engine powering Safari, instead of the V8 engine used by Node.js. Anthropic acquired Bun in December 2025 to power AI coding tools. Bun 1.2 also introduced a unified SQL API and a built-in Redis client. In HTTP benchmarks, Bun handles 3 to 5 times more requests per second than Node.js for certain I/O-bound workloads. For developers building high-throughput payment or notification APIs, these performance gains reduce infrastructure costs. Bun 1.4 also improves package installation, running 10 to 25 times faster than npm. For a T3-stack fixture, Bun completes a first install in 1.41 seconds, while npm takes 18.12 seconds. Bun also delivers 2.6x faster response.body streams through its JavaScriptCore upgrade.
Compatibility and security gaps
Bun 1.4 reports 95% npm compatibility. It passes 97% of node:http and node:fs tests. I find that native addons compiled with node-gyp often lead to breakage. While Bun provides 95% compatibility with most popular packages like Express and Prisma, the lack of a runtime sandbox means I still rely on dependency scanning and lockfile pinning to defend against malicious code. Node 22.4+ includes a permission model. Strapi 5 runs on Node 22, 24, or 26 but cannot run on Bun as a server. The project currently maintains 4.8k open issues in 2026. I find this volume of bugs concerning for enterprise stability. Bun’s implementation of Node-API covers 156 functions, yet modules that link directly against V8 will not work. The Bun 1.4 release added 1,517 newly passing tests from the Node.js suite to improve compatibility. Do developers trust a runtime with 4.8k open issues?
Deployment and specific workloads
Bun runs on Vercel, Railway, and Render. It also supports Windows ARM64 as of version 1.3.10. For AWS Lambda, Bun’s cold start runs 37 times faster than Node.js. I recommend Bun for high-performance APIs. You can use Bun for local development and testing to save time. Bun’s package manager installs dependencies 10 to 25 times faster than npm. This speed is useful for CI/CD pipelines. Bun handles 48,243 requests per second with 105 MB of peak RAM, while Node.js 26.7.0 requires 142 MB for 25,181 requests per second. In a cluster of 100 microservices, this memory efficiency helps lower cloud bills. Bun also includes built-in drivers for PostgreSQL, MySQL, and SQLite. This reduces the need for external dependencies. I find the memory usage of 32 MB for Bun versus 48 MB for Node.js to be a significant advantage for scaling.
