V8
Google's JavaScript engine. Launched with Chrome 2008. Also powers Node.js, Deno, Bun, Cloudflare Workers, Edge. Lars Bak (ex-Sun HotSpot) led initial design.
Written in C++. Tiered compilation: Ignition (interpreter) → SparkPlug (baseline JIT) → Maglev (mid-tier, 2023) → TurboFan (optimizing). Hidden-classes trick for fast property access. WebAssembly support (Liftoff baseline + TurboFan). Competitors: SpiderMonkey (Firefox), JavaScriptCore (Safari). V8 has won the benchmark wars since ~2010.