There's still a lot of WhatsApp Erlang tooling being published, so I'm pretty sure it's mostly still Erlang. I think I still know a couple people who would share with me if it was rewritten, although I left in 2019.
Erlang is simply the right language to build a chat server with, and it doesn't make sense to rewrite it in another language, even though Facebook did that with the server for Messenger. :P
Certainly parts of the WhatsApp stack have changed considerably. No more FreeBSD / no more only a handful of OS processes per node, much less Mnesia (not sure if there's any Mnesia left... I don't get that level of information). I've seen signs that they may have returned to large nodes, so they might be back to millions of connections per node, but that was very much not the case when I left; connection counts had dropped on our FreeBSD nodes because we were doing a lot more on the chat channel and then again because the Facebook nodes we migrated to were so much smaller than our FreeBSD nodes.
Yes, but it is boring telecom projects... so most people aren't interested.
Scala is kind of a more modern alternative.
If doing a twitter like platform, elixir with Phoenix channels could handle around >20k users per host. Very few other options work for that use case. =3
WhatsApp backend in Erlang + used in telecoms
The "WhatsApp used Erlang" story was a decade ago, doubt it is true now.
There's still a lot of WhatsApp Erlang tooling being published, so I'm pretty sure it's mostly still Erlang. I think I still know a couple people who would share with me if it was rewritten, although I left in 2019.
Erlang is simply the right language to build a chat server with, and it doesn't make sense to rewrite it in another language, even though Facebook did that with the server for Messenger. :P
Certainly parts of the WhatsApp stack have changed considerably. No more FreeBSD / no more only a handful of OS processes per node, much less Mnesia (not sure if there's any Mnesia left... I don't get that level of information). I've seen signs that they may have returned to large nodes, so they might be back to millions of connections per node, but that was very much not the case when I left; connection counts had dropped on our FreeBSD nodes because we were doing a lot more on the chat channel and then again because the Facebook nodes we migrated to were so much smaller than our FreeBSD nodes.
I doubt they changed out Erlang/Elixir, as it is mature backbone infrastructure. It has run many telecoms for over 30 years without issue.
The problem is finding talent that knows both distributed systems, and Erlang/Elixir. But Erlang/OTP can replace a lot of expensive kludges. =3
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Yes, but it is boring telecom projects... so most people aren't interested.
Scala is kind of a more modern alternative.
If doing a twitter like platform, elixir with Phoenix channels could handle around >20k users per host. Very few other options work for that use case. =3