zshy is a lightweight, bundler‑free build tool for publishing TypeScript libraries. It reads entrypoint definitions from `package.json` (or `jsr.json`), uses the TypeScript compiler API to emit both ESM and CommonJS modules (rewriting extensions and imports automatically), and updates the package’s `"exports"` and `"bin"` fields so the library can be consumed directly from Node or the browser. It’s aimed at library authors who want reliable `tsc`‑based transpilation without extra bundler configuration.