Brakeman is a free and open-source static analysis security tool specifically designed for Ruby on Rails applications. It scans Rails code to detect potential security vulnerabilities, providing developers with assessments to address issues early in the development process. Known for its speed and thoroughness, Brakeman helps ensure applications adhere to best security practices before deployment. Additional features include detailed warnings, easy setup, and integration with various development workflows, making it an essential tool for Ruby on Rails developers focused on application security.