Elixir is a programming language built on top of Erlang. As Erlang, it is a functional language with strict evaluation, single assignment and dynamic typing built to support distributed, fault-tolerant, non-stop applications with hot swapping. Elixir allows you to invoke Erlang modules without a need to convert data types, therefore there is no hit in performance when invoking existing Erlang code.

The main difference between Elixir and Erlang is syntax and object orientation. Elixir provides a very simple Object Model based on prototype languages with most of its syntax based on Ruby.