Credo

Free plan

What the maker publishes

Analysis

Running `mix credo` analyzes the current project and suggests places to edit code. source

Analysis

It suggests code changes and reports refactoring opportunities, complex code, common mistakes, naming inconsistencies, and style issues. source

Author

The repository names René Föhring as the author. source

Checks

Built-in checks cover consistency, design, readability, refactoring, and warnings, and low-priority checks can be included with strict analysis. source

CI usage

Credo returns a nonzero exit status when it reports issues, supporting shell-based pipelines such as CI workflows. source

Compatibility

Credo aims to stay compatible with the Elixir minor releases listed in the Elixir documentation, which it actively tests on CI. source

Configuration

Credo uses a `.credo.exs` configuration file that can be placed in the project root or its `config/` folder. source

Custom checks

Users can add project or domain specific checks by implementing the `Credo.Check` behavior and configuring the check. source

Installation

The docs recommend adding Credo as a Mix dependency with `only: [:dev, :test]` and `runtime: false`. source

Integrations

The maker lists integrations for IntelliJ, Atom, VS Code, Emacs, Kakoune, Neovim, and Codacy. source

Issue explanations

Users can request an explanation for an issue that includes the check, its configuration options, and how to disable it. source

License

The Hex package lists the Credo package license as MIT. source

License

Credo is released under the MIT License. source

Output

Credo can output command results as JSON. source

Output formats

The CLI supports Flycheck, JSON, and SARIF output formats. source

Plugins

Plugins are modules enabled and configured through the `:plugins` field in `.credo.exs`. source

Publisher

The Hex package lists `rrrene` as the package publisher and owner. source

Purpose

Credo is a static code analysis tool for Elixir focused on code consistency and teaching. source

Teaching

For an issue, Credo can show the check that raised it, its configuration options, and how to disable it. source

Checked against the maker's pages on 9 Oct 2026.