http://highscalability.com/blog/2014/2/26/the-whatsapp-architecture-facebook... "Interesting to note Facebook Chat was written in Erlang in 2009, but they went away from it because it was hard to find qualified programmers." Same year Brian Barton was turned down. Interesting stats 450 million active users, and reached that number faster than any other company in history. 32 engineers, one developer supports 14 million active users 50 billion messages every day across seven platforms (inbound + outbound) 1+ million people sign up every day $0 invested in advertising $8 million investment Hundreds of nodes
8000 cores
Hundreds of terabytes of RAM
70M Erlang messages per second
In 2011 WhatsApp achieved 1 million established tcp sessions on a single machine with memory and cpu to spare. In 2012 that was pushed to over 2 million tcp connections. In 2013 WhatsApp tweeted out: On Dec 31st we had a new record day: 7B msgs inbound, 11B msgs outbound = 18 billion total messages processed in one day! Happy 2013!! ./bernard