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RuboCop

A Ruby linter and auto-formatter that checks code against the community Ruby style guide.

GitHub Download v1.92.2
Stars
12.9k
Forks
3.2k
Licence
MIT
Language
Ruby
Last update
4 days ago
Type
Dev tool

What it is

RuboCop is a static code analyzer for Ruby, sometimes called a linter, and a code formatter. Out of the box it enforces many guidelines from the community Ruby Style Guide. Besides reporting problems, it can automatically fix many of them, and most of its behavior can be changed through configuration options.

  • Run rubocop in a Ruby project folder to list style problems
  • Let RuboCop automatically fix many of the problems it finds
  • Use the built-in LSP server to see the same checks inside a supported editor
  • Add the gem to a Gemfile with require set to false and pin a version range

Great for

  • Ruby developers who want consistent style across a project
  • Teams that want an automated check on code style during development
  • Maintainers of Ruby projects who want to follow the community Ruby Style Guide
  • People who want to upgrade or clean up an existing Ruby codebase

Not ideal for

  • Non-Ruby projects, since it only analyzes Ruby code
  • People who do not want to maintain a configuration file, because many aspects of its behavior are set through configuration options
  • Projects on Ruby versions outside the supported runtimes (MRI 2.7+ or JRuby 9.4+), since the README lists these as the officially supported implementations
Step-by-step guide: how to use RuboCopInstall, first run, examples, tips and FAQs
ESLint vs RuboCopRuboCop vs standard

How to get it

  1. 1

    Install with a package manager

    You'll need: Ruby (MRI 2.7+ or JRuby 9.4+) · RubyGems (the gem command)

    Install the gem

    gem install rubocop
  2. 2

    Run it

    • Install the gem with gem install rubocop
    • Change into a Ruby project folder with cd my/cool/ruby/project
    • Run rubocop to see the results
  3. 3

    Get the most out of it

    • Add RuboCop to your Gemfile with require: false and a version constraint such as '~> 1.92' to avoid unwanted updates
    • Use the built-in LSP server to see results in your editor
    • Configure behavior through the default configuration file and the official docs at docs.rubocop.org

Downloads

Source code (.zip)master branch · straight from GitHubRelease v1.92.2Release notes and sourceOfficial website & docsrubocop.org

Strengths

  • Enforces many rules from the community Ruby Style Guide with little setup
  • Can automatically correct many issues it reports
  • Highly configurable and stable between minor versions, according to the README

Trade-offs

  • Configuration is extensive, so tuning it for a project takes effort
  • The README notes that the project is financially supported through donations and sponsorships, so its development pace depends on funding
  • Supported runtimes are limited to MRI 2.7+ and JRuby 9.4+ per the README

How it compares

ProjectStarsTypeLevelUpdatedBest for
rubocop (this)12.9kDev toolbeginner4 days agoRuby developers who want consistent style across a project
eslint27.6kDev toolintermediate4 days agoJavaScript developers who want automatic checks on their code
standard29.4kDev toolbeginner1.3 years agoJavaScript projects where the team wants consistent style without debating rules
static-analysis14.9kCurated listbeginner5 days agoDevelopers looking for a linter or analyzer for a specific language
ruff50.4kCLIbeginner4 days agoPython developers who want one tool for linting and formatting
jekyll51.7kDev toolintermediate24 days agoDevelopers who want a blog or simple website built from plain text files

Stats synced from GitHub. The assessment above was drafted with AI from the project's README on 2026-10-29 and may miss recent changes — check the README before relying on a command. MIT licence: free to use, modify and distribute, including commercially, as long as you keep the copyright notice.