rcsjta

Yeah... I just started getting back into building sms/mms/rcs apps on Android and oh boy. It's much more of a mess than I expected, and much more "oh so it's basically just Google now, and they seem to be trying to lock it down further" than I expected (or hoped). And you can't even implement it yourself because it requires special permissions on Android, which you can only get if you're a carrier/oem-blessed app. And the early "you'll be able to build other apps, there will be an API like this: https://github.com/android-rcs/rcsjta" promises (which would put it on par with sms/mms) never materialized, despite a reference implementation that did exactly that over a decade ago. At this point I'm just totally against RCS and I'm intentionally turning it off. Why hand all of your messaging communications over to Google, when they've got s

There have been dozens, called anything from Message+ to Joyn. Most seem to be shutting down, though, because nobody used RCS since its inception from somewhere around 2009 and renewed interest in launching RCS services around 2012. There are a few implementations on Github. https://github.com/android-rcs/rcsjta seems to be the most complete but uses an older version of the spec. https://github.com/Hirohumi/rust-rcs-client is a modern implementation. The spec is here: https://www.gsma.com/solutions-and-impact/technologies/netwo... if you're looking to implement it yourself.

It seems people are, but not anyone with a big name: https://jibe.google.com/partners/messaging-partners/ I'm guessing it's provisioned this way. https://developers.google.com/business-communications/rcs-bu... EDIT: https://github.com/android-rcs/rcsjta

There are some partial/mostly finished RCS stacks out there, like this one: https://github.com/android-rcs/rcsjta However, some carriers require authentication through the SIM card. On Android, you can do this as a system app (so you'd need to include it in a custom ROM), on iOS I don't think the necessary API is exposed. There are a whole bunch of authentication options, though, and some of them can be implemented by a messenger without special permissions. RCS is MASSIVE though. Custom ROMs are by design technically incompliant with the full spec (as the money transfer API spec forbids RCS running on "jailbroken" devices). You can grab a copy of the spec (doesn't include E2EE yet) from last year here: https://www.gsma.com/solutions-and-impact/technologies/netwo... Just for reference: page 274 has an example "SMS" message; the eventual f