Bun

Bun is the JavaScript runtime that wants to replace everything: Node.js, npm, webpack, and Jest in a single binary. Written in Zig with JavaScriptCore (not V8), it cold-starts in 8-15ms, installs dependencies 20-40x faster than npm, and handles 120k requests/sec in synthetic benchmarks.

Node.js is still the production bedrock — 100% npm compatibility, 15 years of institutional knowledge, enterprise LTS support. Deno is the security-conscious alternative with a permission model Bun lacks entirely. But for developer experience, Bun is unmatched: one tool for runtime, package management, bundling, and testing.

Use Bun for greenfield projects, serverless functions where cold starts matter, and CI pipelines where 47-second installs beat npm's 28 minutes.

The catch: 98% npm compatibility means the 2% that breaks could be your critical dependency — especially native C++ bindings or V8-specific modules. The "Sustainable Use" license has commercial restrictions. And in production with real databases and business logic, the raw speed advantage over Node.js largely disappears.