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Build Status

Elixir is a dynamic, functional language designed for building scalable and maintainable applications.

For more about Elixir, installation and documentation, check Elixir's website.

Compiling from source

To run Elixir from source, clone this repository to your machine, compile and test it:

git clone
cd elixir
make clean test

Note: if you are running on Windows, this article includes important notes for compiling Elixir from source on Windows.

If Elixir fails to build (specifically when pulling in a new version via git), be sure to remove any previous build artifacts by running make clean, then make test.

If tests pass, you are ready to move on to the Getting Started guide or to try Interactive Elixir by running bin/iex in your terminal.

However, if tests fail, it is likely you have an outdated Erlang version (Elixir requires Erlang 18.0 or later). You can check your Erlang version by calling erl in the command line. You will see some information as follows:

Erlang/OTP 18 [erts-7.0] [source] [smp:2:2] [async-threads:10] [hipe] [kernel-poll:false]

If you have properly set up your dependencies and tests still fail, you may want to open up a bug report, as explained next.

Bug reports

For reporting bugs, visit our issues tracker and follow the steps for reporting a new issue. Please disclose security vulnerabilities privately at


We welcome everyone to contribute to Elixir and help us tackle existing issues! To do so, there are a few things you need to know about the code. First, Elixir code is divided in applications inside the lib folder:

  • elixir - Contains Elixir's kernel and stdlib

  • eex - Template engine that allows you to embed Elixir

  • ex_unit - Simple test framework that ships with Elixir

  • iex - IEx, Elixir's interactive shell

  • logger - The built-in logger

  • mix - Elixir's build tool

You can run all tests in the root directory with make test and you can also run tests for a specific framework make test_#{NAME}, for example, make test_ex_unit. If you just changed something in the Elixir's standard library, you can run only that portion through make test_stdlib, as test_elixir also runs tests for the other projects (EEx, ExUnit, etc.).

In case you are changing a single file, you can compile and run tests only for that particular file for fast development cycles. For example, if you are changing the String module, you can compile it and run its tests as:

bin/elixirc lib/elixir/lib/string.ex -o lib/elixir/ebin
bin/elixir lib/elixir/test/elixir/string_test.exs

To recompile (including Erlang modules):

make compile

If your contribution fails the build during the bootstrapping of the language, you can reproduce it locally by deleting all of Elixir beam files and compiling again:

make clean_exbeam compile

Or to rebuild everything from scratch without running tests:

make clean compile

More tasks can be found by reading the Makefile.

After your changes are done, please remember to run the full suite with make test.

From time to time, your tests may fail in an existing Elixir checkout and may require a clean start by running make clean compile. You can always check the official build status on Travis-CI.

With tests running and passing, you are ready to contribute to Elixir and send a pull request. We have saved some excellent pull requests we have received in the past in case you are looking for some examples:

We usually keep a list of enhancements and bugs in the issue tracker. For proposing new features, please start a discussion in the Elixir Core mailing list. Keep in mind that it is your responsibility to argue and explain why a feature is useful and how it will impact the codebase and the community. Finally, remember all interactions in our official spaces follow our Code of Conduct.

Reviewing changes

Once a pull request is sent, the Elixir team will review your changes. We outline our process below to clarify the roles of everyone involved.

All pull requests must be approved by two committers before being merged into the repository. In case any changes are necessary, the team will leave appropriate comments requesting changes to the code.

The Elixir team may optionally assign someone to review a pull request. In case someone is assigned, they must explicitly approve the code before another team member can merge it.

When review is completed, your pull request will be squashed and merged into the repository.

Building documentation

Building the documentation requires ExDoc to be installed and built alongside Elixir:

# After cloning and compiling Elixir, in its parent directory:
git clone git://
cd ex_doc && ../elixir/bin/mix do deps.get, compile
cd ../elixir && make docs

This will produce documentation sets for elixir, mix, etc., under the doc directory. If you are planning to contribute documentation, please check our best practices for writing documentation.

Development links


"Elixir" and the Elixir logo are copyright (c) 2012 Plataformatec.

Elixir source code is released under Apache 2 License.

Check NOTICE and LICENSE files for more information.