Elixir

mise installs precompiled Elixir releases from Hex. Elixir runs on Erlang/OTP, so install Erlang as well.

Quick start

Declare Erlang and an Elixir build compiled for the same OTP major:

mise use erlang@29 [email protected]
mise exec -- elixir --version

elixir --version reports both the Elixir and the Erlang/OTP version, which helps diagnose a mismatched pair. When both tools are configured, mise installs Erlang before Elixir.

In an existing Mix project, run mise exec -- mix deps.get to fetch the application's dependencies; selecting Elixir does not install them. Add -g to mise use to set personal defaults.

Choosing a version

Hex publishes each Elixir release compiled for several Erlang/OTP majors, as X.Y.Z-otp-NN. Pick the build whose suffix matches your Erlang major:

Request	Selects
[email protected]	Elixir 1.20.4 compiled for OTP 28
[email protected]	The Elixir 1.20.4 build without an OTP suffix
[email protected]	The newest 1.20.x, compiled for the newest OTP it supports
elixir@latest	The newest release, compiled for the newest OTP it supports

A prefix such as 1.20 or latest picks the newest OTP variant. That only matches your Erlang when Erlang is also on its newest major, so pinning Erlang to an older major while Elixir stays on latest gives a mismatched pair. List the builds with mise ls-remote elixir 1.20.

Version files

mise can read .exenv-version. Enable it for Elixir:

mise settings add idiomatic_version_file_enable_tools elixir

This changes your global config. Add --local to enable it in the project's mise.toml instead. See idiomatic version files.

Hex, Rebar and Mix archives

Unless MIX_HOME or MIX_ARCHIVES is already set in your shell or in [env], mise sets them to directories inside the selected Elixir version:

Variable	Value
MIX_HOME	<install>/.mix
MIX_ARCHIVES	<install>/.mix/archives

mise also puts <install>/.mix/escripts on PATH. As a result, mix archive.install, mix escript.install, Hex and Rebar are per Elixir version. After installing a new Elixir version, install Hex and Rebar again:

mise exec -- mix local.hex --force
mise exec -- mix local.rebar --force

To share them across versions, set both variables and put the shared escripts directory on PATH. mise does not override a MIX_HOME or MIX_ARCHIVES that your shell or [env] already sets:

mise.toml

[env]
MIX_HOME = "{{env.HOME}}/.mix"
MIX_ARCHIVES = "{{env.HOME}}/.mix/archives"
_.path = ["{{env.HOME}}/.mix/escripts"]

How mise installs Elixir

mise downloads the build's zip archive from builds.hex.pm and runs elixir --version with the configured Erlang on PATH to check it. mise lock records the checksum Hex publishes for the build.

An installed plugin named elixir takes precedence over the built-in installer. If mise behaves differently from this page, check mise plugins ls and see selecting another implementation.

Tool options

Elixir has no Elixir-specific options. Generic options such as install_env, postinstall and os work as described in tool options. install_env reaches only the elixir --version check and postinstall commands; it does not set MIX_HOME or other variables for later use. Set those in [env].