Erlang is a functional concurrency-oriented language with extremely low-weight user-space "processes", share-nothing, message-passing semantics, built-in distribution, and a "crash and recover" philosophy proven by two decades of deployment on large soft-realtime production systems.
Erlang is used to build massively scalable production grade systems with requirements of high availability. Some of its uses are in telecoms, banking, e-commerce, computer telephony and instant messaging. Erlang's runtime system has built-in support for concurrency, distribution and fault tolerance.
Our Erlang & Elixir passion is displayed in our products. We build concurrent, secure and high-available systems that can scale to any number. The technologies used in our SaaS applications landscape are hovering around Erlang world, to produce performant and resilient applications that stand the Best of time, with more concentration towards scalability during Implementation, and usage of robust tools and frameworks such as RabbitMQ, Riak, Rebar3, Ejabberd, BEAM, Yaws, mnesia and many more...
A Well-said article from FC on Erlang about it's usage in Whatsapp, "How do you support 450 million users with only 32 engineers? For WhatsApp, acquired by Facebook, the answer is Erlang, a programming language developed in the ’80s that is finally having its moment in the spotlight." Read More at inside-erlang-the-rare-programming-language-behind-whatsapps-success