The TypeScript type checker,
inside a Cloudflare Worker.
tsc-rs is a Rust port of the TypeScript 7 compiler.
Compiled to WebAssembly, it runs in memory, inside this Worker: no container, no file system, no Node.
Paste code below and get the same errors tsc gives you.
Why
Agents write code against tools. A wrong argument or a made-up method should fail in milliseconds, before the code runs, not halfway through a job.
How
The checker is one WebAssembly module, bundled with the Worker. Each request gets a fresh instance and an in-memory file system holding your two files.
Proof
The repo builds the module from tsc-rs source and checks the same cases in Node, in a local Worker, and against this deployed Worker.
| Measured | Value |
|---|---|
| This page's last check (round trip) | — |
| Warm check in Node, median (same module) | 74 ms |
| WebAssembly module | __WASM_MB__ MB |
| tsc-rs commit | dfb3ca6 |