TechCrunch is reporting on WhatsApp passing the 800,000,000 active users mark. Almost exactly a year ago, it was at 500 million active users. I don’t care much about WhatsApp’s business or service, but from the technical point of view this is quite significant. That’s almost a million active users acquired every day for the last year. That’d be a challenge for anyone to handle. Thinking that this growth might have been not too linear gives me digital goose bumps.
I haven’t seen anything recent describing their infrastructure, but this article from last year provides a starting point for the imagination: Erland + FreeBSD + 550 servers, with preference for larger box with loads of RAM and cores. I’m sure that have grown quite a bit in a year too.