RuboCop Rails is a RuboCop extension gem that adds Rails-specific "cops" (lint rules) for flagging deprecated APIs, unsafe patterns, and style deviations in Ruby on Rails codebases. It was split out of RuboCop core into its own gem and repository in 2018 and is maintained by the same community team that maintains RuboCop itself, under the rubocop GitHub organization, not by a commercial vendor. It targets Rails 4.2 and newer and is configured through the same .rubocop.yml mechanism as core RuboCop, including a TargetRailsVersion setting to scope which cops apply. Like the rest of the RuboCop ecosystem, it flags code for a human to fix; it does not rewrite application logic or perform migrations on its own.
Legacy Application Modernization
RuboCop Rails is a RuboCop extension gem that adds Rails-specific "cops" (lint rules) for flagging deprecated APIs, unsafe patterns, and style deviations in Ruby on Rails codebases. It was split out of RuboCop core into its own gem and repository in 2018 and is maintained by the same community team that maintains RuboCop itself, under the rubocop GitHub organization, not by a commercial vendor. It targets Rails 4.2 and newer and is configured through the same .rubocop.yml mechanism as core RuboCop, including a TargetRailsVersion setting to scope which cops apply. Like the rest of the RuboCop ecosystem, it flags code for a human to fix; it does not rewrite application logic or perform migrations on its own.