The lemmy-js-client docs have the HTTP Enpoints somewhere in there and if you click on "form" for a specific endpoint, it shows you the parameters.
Bigger problem is that nothing has any description, but all in all the docs are quite bad, even if complete.
I had known Mastodon for quite some time but never used it until lots of people came over there from Twitter (which I had never used) and then I set up my own instance.
And now I've also set up my own Lemmy instance, I am still using Reddit aswell, but I hope Lemmy gets enough activity for it to be actually useful (seems to be on a good path).
(Yes, I don't mix Mastodon and Lemmy, because Lemmy just works so different from most other ActivityPub software, it would just confuse me.)
Also I have used Matrix for quite a long time now.
On Mastodon everyone frowned upon the Twitter mirrors, I suspect it would be the same here.
Mastodon is quite nice to host, even has a "single user instance" setting, also it has lots of users.
@jstsmthrgk
@lemmy.jstsmthrgk.eu