Erlang is a programming language traditionally used to build massively scalable soft real-time systems with requirements on high availability. Some of its uses are in telecoms, banking, e-commerce, computer telephony, realtime application and instant messaging. Erlang’s runtime system has built-in support for concurrency, distribution and fault tolerance.

High Availability/Reliability
- Simple and consistent error recovery and supervision hierarchiess.
- Built-in fault tolerance.
- Software upgrade (hot code loading) during runtime.

Scalability/Heterogeneity
- Run on a variety of platforms, supports heterogeneous networks.
- Network aware runtime, out-of-the-box distributed architectures.
- Lightweight processes, highly scalable transparent or explicit concurrency.

Less Effort
- Functional programming language, high abstraction level, concise readable programs.
- 4–20 times less code compared to C/C++/Java.
- Suitable for rapid prototyping.
- Powerful middleware and libraries (OTP).

For more information erlang.org