Since Discord has decided to set itself on fire you might be looking for an alternative. Fluxer is open source (AGPL), selfhostable and based in Sweden. But maybe wait a while before you try to install the server yourself because the dev writes on github:
I know it’s hard to resist, but please wait a little longer before you dive deep into the current codebase or try to set up self-hosting. I’m aware the current stack isn’t very lightweight. In the next update, self-hosting should be straightforward, with a small set of services: Fluxer Server (TypeScript) using SQLite for persistence, Gateway (Erlang), and optionally LiveKit for voice and video.
The developer hosted instance has a Nitro-like premium tier for their service named Plutonium, if you selfhost you get all the premium features for free.
Fluxer is not federated (yet), but according to the website, federation is planned in the near(-ish) future. Furthermore the service is a bit spotty at the moment as they are fighting with an unusually big influx of new users.
Of all the discord clones, this one does look promising I must admit, especially since the dev has mentioned they’d be open to incorporating federation and some encryption abilities down the road. The GPL license is a good mark, and the dev seems pretty chill. Downside is that’s it’s still very rough and in more of a visually polished alpha state. The dev mentioned they’re about to release a major refactor of the codebase, which they hope will fix the sluggishness the server is experiencing after an influx of new users from the Discord dumpster fire.
Personally, I’d still suggest Movim over Fluxer at the moment.
Movim already has a proven scalable back-end, it’s already federated, already provides good encryption, has 90% feature parity with Discord such as Chats, group video calls, screen-sharing with audio (requires chromium browser to share audio for now), its made in the EU, and it’s ready right now, not some time in the future (if Discord users fleeing discord try Fluxer, they’d be likely to bail on it due to the current bugs and just go back to discord). The Movim developer is also currently working on adding in discord-like channels and rooms.
But that’s just my 2 cents. Fluxer is one to keep an eye on for the future, though.