Its goal is to help synchronize types between TS, Rust, and Python (more to come). Two main use cases are the API client libraries and client-server interop, i.e., a TS web app talking to a Rust server.
I focused on making it as flexible as possible but always produced idiomatic types that look and feel like they were carefully crafted by humans. It was a challenge, e.g., I had to test 7 Python versions for every language feature or had to implement Rust literals runtime.
It's written in Rust, btw ;-)