In 2016, WhatsApp reached more than a billion users. They managed to serve this scale with only 50 engineers and here’s a dive into the engineering culture and tech stack that made this possible.
WhatsApp’s Engineering culture consists of 3 main principles
The tech stack revolves around 3 core components: Erlang, FreeBSD and SoftLayer.
Erlang was designed for concurrency from the start, and fault tolerance is a first class feature of the language. The decision to use FreeBSD was made by the founders of WhatsApp, based on their previous experience at Yahoo!
They picked SoftLayer for two main reasons: