Programming language and runtime environment, much like Java, developed by Ericsson for use in telecommunication systems. Noteworthy features include soft real-time capability, good fault tolerance, multithreading and easy distribution of the workload.

Both the development libraries (called OTP) and the runtime environment is open source.

Hello World in Erlang:

-module(hello).
-export([hello_world/0]).
	
hello_world() -> io:fwrite("hello, world\n").

Erlang is also the unit used for measuring workload over a communication link, where 1 is maximal utilization of the link.