Elixir: Install & Toolchain

The Toolchain Stack

It helps to know what you are installing. Elixir does not ship its own virtual machine — it compiles to the same bytecode as Erlang, so a matching Erlang/OTP release is a hard prerequisite. One Elixir version supports a specific range of OTP versions; when you see the pair written as 1.20-otp-28, that is the contract.

Install Paths

Version managers (recommended)

A version manager installs OTP and Elixir side by side and lets you switch per project — the same role pyenv plays for Python or rustup for Rust.

# Using mise (the modern version manager for the BEAM)
mise use -g erlang@28
mise use -g elixir@1.20

# Or the classic asdf flow
asdf plugin add erlang https://github.com/asdf-vm/asdf-erlang.git
asdf plugin add elixir https://github.com/asdf-vm/asdf-elixir.git
asdf install erlang 28.0
asdf install elixir 1.20.0
asdf global erlang 28.0
asdf global elixir 1.20.0

Official installers and Docker

Windows and macOS have official installers from the Elixir team, and most Linux distributions ship packages (often older). For CI or evaluation without any install, use the official Docker image:

# Pin both the Elixir and OTP versions explicitly
docker run --rm -it elixir:1.20-otp-28 iex

# Or use Docker as your whole dev environment
docker run --rm -it -v "$PWD":/app -w /app elixir:1.20-otp-28 bash

Verify Each Layer

Run these four commands after installing. They confirm the runtime, the shell, the build tool, and the package manager independently — so if something is broken you know which layer.

elixir -v        # prints Elixir and Erlang/OTP versions
iex              # opens the interactive shell (exit with Ctrl+C twice)
mix --version    # build tool
hex --version    # package manager (install with: mix local.hex)

Your First Session

iex is the fastest way to feel the language: every expression is evaluated and printed immediately, exactly like a Python REPL — with the twist that you can spawn processes and inspect the runtime from the same prompt.

iex> 40 + 2                 # every expression returns a value
42
iex> "elixir" |> String.upcase()   # the pipe works in the shell too
"ELIXIR"
iex> self()                 # iex itself is a BEAM process with a pid
#PID<0.108.0>
iex> Process.info(self())[:memory]   # inspect your own process heap
16864
iex> h String.split         # h/1 opens the docs for any function

Editors and Livebook

• VS Code / JetBrains — install ElixirLS (or the newer Expert server) for completion, inline docs, and the debugger. It reads the same compile artifacts as mix.
• Livebook — an interactive notebook for Elixir with markdown + code cells, visual outputs, and Mix.install for dependencies. Install with mix install livebook and run livebook server. Excellent for exploring Nx and data work in Numerical & Embedded Elixir.
• Formatter — ships with Elixir; run mix format and commit a .formatter.exs so the whole team's code looks identical.

The Mix Project Skeleton

Create your first project now — every later chapter assumes this shape.

mix new explorer --module Explorer
cd explorer
mix test          # the generated project ships with one passing test
tree -L 2         # inspect the layout below

Practice

1. Install Elixir 1.20 on your machine (or run it in Docker), then paste the iex session above and confirm every line works.
2. Create the explorer project and add one function to lib/explorer.ex; run mix test again.
3. Start Livebook, create a notebook, and install one Hex package in a cell with Mix.install([{:req, "~> 0.5"}]).
4. Write down which command you would run to check why a build fails before blaming your code: the shell, the build tool, or the package manager?

Next: Syntax & Expressions