eqwalizer - A type-checker for Erlang

Created at: 2022-06-22 16:57:52
Language: Erlang
License: Apache-2.0


A type-checker for Erlang.

Using it with rebar3 projects

  1. Use OTP 25

  2. Download the elp binary for your system from https://github.com/WhatsApp/eqwalizer/releases

    On Mac you will probably get the following message when trying to run the executable the first time: "elp cannot be opened because the developer cannot be verified.". To solve this, go to Preferences > Security and Privacy and add an exception. Alternatively, you can build elp from source.

  3. Add eqwalizer_support dependency and eqwalizer_rebar3 plugin to your rebar3 project definition (see below)

  4. From the project directory run:

  • elp eqwalize <module> to type-check a single module
  • elp eqwalize-all to type-check all src modules in the project

Adding eqwalizer_support and eqwalizer_rebar3:

{deps, [
        {branch, "main"},

{project_plugins, [
        {branch, "main"},


Please refer to the FAQ document for answers to some common questions, including:

  • What's the difference between eqWAlizer and Dialyzer?
  • Why not extend Dialyzer, rather than creating a new tool?
  • What about Elixir?


eqWAlizer is Apache licensed.