There are really two federated protocols, xmpp and matrix. Matrix is pretty young but looks good, they just added e2e encryption. Check out the Riot client, we

There are really two federated protocols, xmpp and matrix. Matrix is pretty young but looks good, they just added e2e encryption. Check out the Riot client, web, android and ios. The apps are even native. Plus, you don't have to show your phone nr.