Happo is a tool designed to enhance user interface development by providing automated cross-browser screenshot testing, ensuring developers can confidently identify UI changes with each new commit. Integration with CircleCI is simplified through the Happo CircleCI orb, which abstracts boilerplate setup in the CI environment, allowing for easy configuration via the .circleci/config.yml file. Users must set API tokens in environment variables obtained from happo.io to facilitate this process. The orb supports additional customization through the happo/run_happo command, allowing for pre- and post-testing steps. Once configured, the Happo CircleCI orb generates screenshots for each commit, offering comparison links for pull requests and branch builds, and posts build statuses directly to associated GitHub repositories. This integration, part of CircleCI’s Technology Partner Program, aims to streamline the CI workflow for developers, as expressed by Happo founder Henric Trotzig.