I just finished a dsn parser and now I am planning to write a pcb router. All in rust. The plan is to have a wasm/wasi version as well so routing is possible in the browser.

Very interesting. Is it or will it be open source? Any links?

dsn parser is open source, https://github.com/dilawar/dsn-parser (WIP). Some part of PCB routing will be open-source (MIT).