Beeper is based on Matrix and the bridges they use are almost all open source. It's an amazing Matrix client (including on Android and, reportedly, iOS) and tha

Beeper is based on Matrix and the bridges they use are almost all open source. It's an amazing Matrix client (including on Android and, reportedly, iOS) and that makes it pretty great at everything else. Though the Discord integration could use a bit of work still. Texts looks entirely proprietary and the FAQ says they're working on an iOS app.