bine VS noise_wiki

That is a bummer, although for now I guess it would be better than nothing to reach out to api.protonmail.ch through Tor. I'd be more motivated if it were an onion though. I had a look at the likely places it would need to be modified: https://github.com/ProtonMail/proton-bridge/search?q=dial and I think all it would take is to make a struct that extends https://github.com/cretz/bine so that it implements TLSDialer to make a drop-in Tor based connection. That would be very thorough and pretty escape-proof. I'm steadily talking myself into doing it...

Sure. I wrote https://github.com/cretz/bine (though I admittedly don't work on it much these days). I just have a few-line daemon that starts an HTTP (or gRPC or whatever) server on ephemeral onion service. Then I use that onion ID to access it (via TorBrowser or Orbot or a client built with the same library).

> Or a self-hosted option where the API could be deployed to the company's cloud of choice?

Can put it on Tor and give an ephemeral onion link (I wrote https://github.com/cretz/bine to help w/ just these use cases). So people could access via Tor browser or via the same CLI with a "client"/"get" command. Can even have the ephemeral server determine its been HTTP "GET"d and kill itself. Then you don't even need a public website.

Shameless plug, I also wrote a simple lib that makes onion services easy: https://github.com/cretz/bine (OP's project uses a fork of it and I plan on putting more time into it soon)

https://github.com/ipsn/go-libtor and https://github.com/cretz/bine are excellent libraries to get you started. They do exactly what you are asking.

How do you mean? Could you link to where you could find that? Because I searched for 'metadata' in the Noise Protocol repository and came up with nothing (https://github.com/noiseprotocol/noise_wiki/search?q=metadat...)