Protobuf is a fairly simple format, but the way people are first introduced to it often doesn't speak to them. That is how it was for me at first. I tried to address that in two ways: simple visual diagrams where a picture does the work better than prose, and interaction so you can get a feel for the language and how it behaves without installing anything.

Some parts of the guide run a real Protobuf compiler, bufbuild/protocompile, in the browser through WASM. It's the same compiler the buf CLI uses.

Feedback welcome.

Disclosure: I work at Buf, and Buf owns the domain. The guide started as a side project before I joined.