https://techcrunch.com/2023/12/05/beeper-reversed-engineered-imessage-to-bring-blue-bubble-texts-to-android-users/

The push to bring iMessage to Android users today adds a new contender. A startup called Beeper, which had been working on a multi-platform messaging aggregator, is now launching a new app called Beeper Mini which will allow Android users to send and receive end-to-end encrypted iMessage chats for just $1.99 per month. Beeper Mini was made possible because the team behind the app has managed to reverse engineer the iMessage protocol, they say.

“That’s the big breakthrough,” explains Beeper co-founder and CEO Eric Migicovsky, previously the founder of smartwatch startup Pebble. “We’re not actually a middleman anymore. The research that we’ve done is actually reverse engineering the iMessage protocol, down to the lowest layer of the protocol. So Beeper Mini doesn’t use a Mac server as a relay like all the other apps — they have a Mac Mini in a data center somewhere. And when you send a message, you’re actually sending a message to the Mac Mini, which then forwards it to iMessage,” he explains. “Beeper Mini is a native implementation of the iMessage protocol.”