I've been looking for info about this for months, as it was obviously a part of the EU's anti-gatekeeping legislation from last year, but I couldn't find any info. Specifically I wanted to know which apps would be able to communicate with WhatsApp - Telegram? Signal? Something else?
And now that there's an article, it's behind a paywall...
Edit: managed to read it through Firefox's reader mode. Unfortunately they don't know, but not for lack of trying:
So far, it is unclear which companies, if any, are planning to connect their services to WhatsApp. WIRED asked 10 owners of messaging or chat services—including Google, Telegram, Viber, and Signal—whether they intend to look at interoperability or had worked with WhatsApp on its plans. The majority of companies didn’t respond to the request for comment. Those that did, Snap and Discord, said they had nothing to add.
The only service they mentioned that definitely will have chat interoperability is Facebook Messenger.... Yeah, no fucking thanks.
Specifically I wanted to know which apps would be able to communicate with WhatsApp
WhatsApp will allow any service to communicate with their network. But wether or not any do is entirely up to those other apps. I think there's very little chance Signal will ever interoperate with anything for example. iMessage surely won't either.
Technically it shouldn't be difficult, because almost every chat app these days uses the same protocol (Signal which is an unofficial industry standard and soon to be an official one). The question is how well it fits with their business model. And most companies don't share their business model.
The other issue is the recipient needs to opt in. You won't be able to send messages to just anyone... and if spam is an issue then everyone might turn it off.
The bigger question for me is wether or not you will be able to use a third party app to access WhatsApp. As in full access, view all messages, view contacts, create messages, receive push notifications, etc etc. It looks like the DMA might allow a return to software like Adium which is an open source messaging app that used to be able to log into almost any messaging service. These days none of the most popular services are available in the app, so almost nobody uses it.
Adium… now that’s a name I have not heard for a while. Used to have a super nice customized version to chat with friends on various platforms. It was amazing. Thanks for the nostalgia trip!