# How to use To extend the Rust library, make sure the functions you're exporting have `#[no_mangle]` derived and they `extern "C"`. To use, just import `{func} from "./lib.rs"`. To make sure args and return types match, go to `@types/lib.rs/config.ts` and change the types of args and returns. ``` bun i bun dev ``` ``` open http://localhost:3000 ```