We usually don't use this blog to talk about the technology stack behind WhatsApp, but today we wanted to share with you an awesome milestone we have reached.

Over the past few months we have been making a lot of improvements to our servers to increase the performance, uptime and scalability. Today we have tuned some knobs, shifted some traffic around and achieved 1 million established tcp sessions on a single machine (and with memory and cpu to spare!)

$ netstat -an | grep -c EST 1016313

We are extremely proud of this achievement and wanted to share with other tech minded people out there. For those curious how we did it, the technology on the backend is simple: FreeBSD + Erlang

P.S. - we are hiring in both client and server teams, so send your resume to jobs at whatsapp dot com if you are interested.