SWC
"Speedy Web Compiler" — Rust-based TypeScript/JavaScript compiler by Donny Wong (2017). 20× faster than Babel.
Drop-in replacement for Babel + Terser in many flows. Powers Next.js (since v12, 2021), Deno, Parcel 2, Rspack. Plugin API in Rust or WebAssembly. JIT-compiles TS/JSX → ES5/ES2020 + minifies + bundles.
Competitor: esbuild (Go-written, faster on some workloads), tsc (TypeScript official, more correct but slow), Sucrase (specialised).