WhatsApp is still based on XMPP unless things have changed a lot recently.

svyatoslavpavl · 2026-08-25T15:08:18.000000Z

The protocol is still their stripped down XMPP dialect, yeah. I meant the server side: they rewrote most of the original ejabberd over the years, but it stayed Erlang.

tensor · 2026-08-24T21:12:51.000000Z

What about their signal integration? https://signal.org/blog/whatsapp-complete/

pixelschubsi · 2026-08-25T10:57:55.000000Z

The open protocol variant of that is called OMEMO. Same double ratchet and implemented using Signal's library (the same as used by WhatsApp) in many XMPP clients

tcfhgj · 2026-08-25T13:37:28.000000Z

> the same as used by WhatsApp

source? wouldn't that be a license violation?

pixelschubsi · 2026-08-25T19:12:09.000000Z

WhatsApp paid WhisperSystems (the previous Signal company) for a commercial license. Same as Google. Dual-licensing their encryption protocol library was their main source of income back then.

AFAIK, even today you can fetch the WhatsApp Android apk, extract the zip and do a `strings classes*.dex | grep signal` to find class and package names matching the sources in the signal-protocol-java repository in the Signal GitHub.

alex1138 · 2026-08-24T20:50:59.000000Z

I don't consider WA a product. I don't consider it a viable product. Post-2014/Zuckerberg. Who cares if it's XMPP, it didn't federate

account42 · 2026-08-26T08:33:31.000000Z

Unfortunately it's the de-facto messaging app for normies here, most of whom won't be willing to install another app for just that one weirdo.