[ksec]

>IIRC, Whatsapp backend used to be on Erlang

Used to be? I know WhatsApp switched from FreeBSD to Linux and swapped hundreds bare metal servers to thousands of VMs. I dont think WhatsApp ever swapped / rewrote their system in another language under Facebook.

[thijsvandien]

There was some confusion about that a little while ago: https://news.ycombinator.com/item?id=21111662