The protocol is documented in the official PostgreSQL documentation: https://www.postgresql.org/docs/current/static/protocol.html

I meant a doc explaining roughly the components at https://github.com/MagicStack/asyncpg/tree/master/asyncpg/pr... and how they interact with each other at a high level as it doesn't seem to have comments.

Thanks for the link though, I'll have a look

Yeah, documenting internals sounds like a good idea. At least to make it easier for people to contribute and further improve asyncpg. We'll try to find some time to do that.