a public API is coming! no promises on timelines yet but it's important to us to get it shipped.
It'd be nice to support a "standard" API like MetaWeblog if at all possible. I know some of those (including that one!) is old and creaky, but it's old and creaky—and already has existing tools that work with it. A more modern incarnation of that might be Micropub.
(Also, I noted the "documentation is hard" in Jae's link. If you need help with that, you might able to ping me, depending on time constraints [yours and mine] -- I'm actually a technical writer who specializes in documenting developer APIs!)
Since you're working on an API, I might I suggest the following:
* [IndieAuth](https://indieweb.org/IndieAuth) (itself an extension to OAuth) for login/authentication
* [Micropub](https://indieweb.org/Micropub) for submitting and editing posts
This combination would immediately make cohost work very well as part of the IndieWeb and could make use of the many existing micropub clients out there (so you don't need to write your own mobile client), and would also allow things like using a Cohost account to sign in to IndieAuth-enabled websites as well.
+1, would be nice to be able to make clients for mobile :)
I hope this is still in the cards! The webapp is a good baseline, but letting folks write their own clients is even better.
I know a lot of artists that would love to be able to use PostyBirb to post here while the figure out their new social media landscape and an API is very much needed for that. Really hope this is given the attention it deserves.
From what I've been able to tell, cohost uses tRPC in a monorepo with Preact and Express, so they can't just publicly open up the tRPC endpoint without open-sourcing (please, please, please do that), so they have to build one from scratch.
Really wish this would get implemented ASAP. It's driving me crazy not being able to add CoHost to my Postybirb crossposts!