Test Coverage Rcov https://github.com/relevance/rcov SimpleCov https://github.com/colszowka/simplecov Complexity Flog https://github.com/seattlerb/flog Flog values in your vim console https://github.com/skammer/vim-ruby-complexity Code Churn Churn https://github.com/danmayer/churn Turbulence https://github.com/chad/turbulence Syntax Duplication Flay https://github.com/seattlerb/flay Rubocop https://github.com/bbatsov/rubocop Cane https://github.com/square/cane ERD Entity Relationship Diagrams http://rails-erd.rubyforge.org/ https://github.com/preston/railroady Security Analysis http://brakemanscanner.org/ Tying it all together Code Climate http://codeclimate.com metric_fu https://github.com/metricfu/metric_fu