Design, development and product agency best known in the Ruby community for its open-source gems — most famously factory_bot and factory_bot_rails. At wroclove.rb 2026, total thoughtbot gem downloads on RubyGems were approaching 1.66 billion; Louis pitched the internal slogan '50 bucks says we're in your Gemfile'. Recent gems include Top Secret, Top Secret LLM and Michelle. Runs the AI on Focus weekly livestream. Also collaborates on the Close-Knit healthcare project.