Your initial claim talked about jmap and this looks to me like a full implementation of the RFC in rust. That is the hard part of an email client IMO so I’m not sure I’d agree with your analogy, but you’re saying it made a web app which called a library like this?
Would be interesting to see it, did you publish it yet?
> looks to me like a full implementation of the RFC in rust
Only the client parts. And only the client parts its actually using. JMAP clients can be much simpler than servers. A JMAP server needs the whole protocol. JMAP clients only need to implement the parts they use. Servers also need to parse email message envelopes - which is way more difficult to do correctly than people think. JMAP clients can just use pre-parsed messages from the server.
Anyway, the code is here if you wanna take a look:
https://github.com/josephg/claude-mail
Claude put its JMAP API wrapper code in a child crate (confusingly also called jmap-client).