The fastest* TypeScript type checker** in the world*** has two stars on GitHub

A high speed TypeScript type checker written in C, using cleat.

scripts/fastbuild.sh fast/tttt -p path/to/project # or run from your project directory without arguments

tttt is meant as a drop-in tsc for checking: the same command lines and tsconfigs. Every run behaves like tsc --noEmit, except that a project whose config has emitDeclarationOnly gets its .d.ts and .d.ts.map files written like tsc does. See release/tttt --help for more info.