[tazjin]

This used to be fairly common, back in the old days. Programs like Pidgin unified many messengers into a single app.

For a while, many messengers actually shared underlying protocols (e.g. Google Talk & Facebook were both using XMPP at some point, and you could even cross-message).

Nowadays this is much harder. There's some exceptions (Telegram) with open client protocols, but I wouldn't wanna try and implement something like Discord, it'll be a never-ending tarpit.

[koakuma-chan]

Discord is (or at least was) easy to "implement" because their bot and user API is mostly the same.

[dijit]

until they ban you under the ToS that says “no third party clients”.

https://news.ycombinator.com/item?id=28435490

[theshrike79]

A bot or a bridge isn't a "client".

They just don't want to fight people trying to build a full alternative client for Discord as a bunch of their paid-for stuff is just clien side javascript.