A general-purpose, concurrent, functional programming language used to build massively scalable soft real-time systems with requirements on high availability. Erlang comes bundled with the OTP, the Open Telecom Platform which is a runtime system first developed by Ericsson to handle the Swedish telecom infrastructure in the early 80's. The term Erlang and OTP is today used interchangeably and includes the runtime, the language and ready-to-use components built specifically for the ecosystem. To this day, Erlang is used in various sectors and applications like telecoms, banking, e-commerce, computer telephony and instant messaging. As the language is suitable for critical infrastructure and applications that requires high availability and real-time features, running at scale.