Kimai is a self-hosted, open-source time-tracking application built with PHP 8.3+ and Symfony 6/7. It provides a full-featured web interface and REST API for recording timesheets, managing projects/customers/activities, generating invoices, exporting data (PDF, XLSX, CSV, HTML), and producing reports. The architecture follows a classic Symfony monolith with Doctrine ORM, Twig templating, and Webpack Encore for frontend assets. It supports multi-user, multi-timezone, multi-language, LDAP/SAML authentication, two-factor authentication, and a plugin system via tagged services and compiler passes. The codebase is heavily event-driven, with over 70 domain events and subscribers, and includes a rich set of dashboard widgets, custom form types, and validation constraints. The repository is actively maintained with frequent commits, extensive test coverage (PHPUnit), and continuous integration pipelines.