I did a post about this app in Sep 2022 at #^https://gadgeteer.co.za/beeper-lets-you-use-imessage-on-android-and-windows-without-any-apple-device-but-it-comes-at-a-price/
as it was using quite an innovative way to achieve iMessage use on Android without requiring a Macbook.
It appears that the app has been growing steadily and now integrates numerous different chat services apart from just the commonly used big ones. They have even been rolling out some features that have not gone live on the parent services. There is also now forwarding between services as well as scheduling of messages, voice notes and more.
It runs cross-platform on desktop, Android, iPhone, Android Auto, Chrome OS, and even notifies via a Pebble watch. Chat services connected appear to be Whatsapp, Telegram, Slack, Twitter (X), Instagram, Discord, LinkedIn, IRC (yes really!), Matrix, Facebook Messenger, iMessage, Android SMS, Signal, and Google Chat.
All Beeper chat messages are end-to-end encrypted. Messages sent using Beeper to other chat networks are re-encrypted if the other network supports encryption (like Signal, WhatsApp and iMessage). So yes, you won't be having true E2EE all the way on those services, but a lot depends on what you're actually saying I suppose. There is however full E2EE between any other Beeper users and to Matrix users. They do state though they have zero-access to the contents of messages, so if you lose access to all your devices and your Recovery Code, they will not be able to recover your chat history (the way it should be). Their servers are located in Europe.
They built Beeper on the open source chat protocol Matrix, using its bridges functionality. Unlike other chat networks, there is no lock-in. You’re free to use open source Matrix clients to connect to Beeper, or download your data and move to a different Matrix server and continue chatting with your friends on Beeper.
For those who prefer not to use their default web service that they offer, it is possible to self-host the majority of the Beeper backend yourself. They open sourced all their bridges.
This is what they explain about how they transitioned to going free: "Later this year, we will launch an optional paid subscription, called Beeper Plus, which includes additional features like larger chat history backup, access to multiple network connections, and more. By making Beeper free, more people will feel comfortable sharing it with their friends, enabling more people to start using Beeper. Through the optional paid subscription, we will earn enough money to run the app. Currently, everyone who signs up for Beeper will enjoy a free trial of some features that will be part of Beeper Plus."
I'm thinking that I will now give this a try. I'd like to see how it works, or not, with iMessages (as I no longer have an iPhone) and with Whatsapp/Facebook (as I have no accounts with these services, so maybe this won't work).
See Beeper — All your chats in one app. Yes, really.
A single app to chat on iMessage, WhatsApp, and 13 other chat networks. You can search, snooze, or archive messages. And with a unified inbox, you’ll never miss a message again.