Alt ForumsSpacebar
Formerly known as "Fosscord", I think it was created in 2020, though it didn't really take off until around 2021 when it was crossposted on Hacker News and on a bunch of subreddits and then faded into obscurity until now, thanks to Discord and its ID BS.
In short, it's a reverse-engineering project to how Discord works. You can also host your own instance (without federation), but it requires to follow a lot of steps (most of them are optional if you don't have plans to make a big/public instance), though you can just use Docker (docker-compose) to avoid too much hassle (last time I tried making my own instance I was getting errors while setting a PostgreSQL DB and I ended up giving up lol). And I think it's almost 1:1 to Discord's API so I think you can migrate your Discord bots you made on Discord.JS for example to Spacebar without having to do so much changes.
There's also a public instance for it but it requires using a client to connect on it. Seems like the most recommended one is Fermi, which has a similar aspect to Discord.
And well, as is usually the case with this kind of projects, don't expect a very stable experience.
