I work on the Mellium project and sometimes on XEPs. Bike mechanic during the day, but also sometimes freelance software development.
Hire me: https://willowbark.org/
I will say that it’s worth being careful: there’s no option for a backup XMPP account (so your account better have perfect uptime) and I very rarely have incoming phone calls actually work (calling out works, calling in is pretty random, most of the time it doesn’t even ring). Also the UI on the client is still pretty bad (especially for group texts, which are almost unusably bad).
All that being said, it’s a great service, just know what you’re getting into before you make it your primary phone number, it’s not nearly as polished as they make it sound.
There’s also a blog post here: https://blog.jmp.chat/b/cheogram-android-stickers-2023