Overview: Kimai is a professional, open-source time-tracking application designed for freelancers, teams, and organizations that need precise control over their time data. Built on Symfony and Doctrine, it offers a robust alternative to commercial SaaS tools by enabling full self-hosting with support for multi-user environments, multiple timezones, and over 30 languages. Kimai was created to address the need for transparent, customizable time-tracking without vendor lock-in, making it ideal for users who require data sovereignty, compliance, or integration with internal systems. Whether you’re managing a single freelancer’s hours or hundreds of team members across global offices, Kimai provides the infrastructure to track, report, and invoice time with enterprise-grade features—all under your control.
What You Get
- Multi-user & role-based permissions - Assign granular roles and team-specific access controls to users, ensuring that employees only see relevant projects, customers, and time entries.
- JSON API - Expose time tracking data via a documented REST API for integration with internal tools, dashboards, or automation workflows.
- Invoicing & billing - Generate professional invoices directly from tracked time entries with customizable templates, tax rates, and currency support.
- Multi-timer & punch-in/punch-out mode - Track time either by starting/stopping timers manually or via a simple punch-in/out interface for shift workers.
- SAML/LDAP authentication - Integrate with existing corporate identity providers for secure, centralized user management without manual account creation.
- Two-factor authentication (2FA) with TOTP - Enforce additional security for user logins using time-based one-time passwords.
- Data exports - Export time entries and reports in CSV, PDF, or Excel formats for accounting, payroll, or compliance purposes.
- Customizable rates & budgets - Define user-, customer-, or project-specific hourly rates and set time or monetary budgets with alerts for overruns.
- Advanced reporting & filtering - Create custom reports using filters by date, project, customer, tag, or user with visual charts and export options.
- Plugin system - Extend functionality via a marketplace of plugins (both free and paid) for features like calendar sync, Slack notifications, or custom reporting.
- Multi-language support - Full interface translation in over 30 languages via Weblate, with community-driven translations maintained in real time.
- Responsive design with Tabler UI - Fully functional on desktop, tablet, and mobile devices with a clean, modern interface built on Tabler and Bootstrap.
Common Use Cases
- Building a freelance invoicing workflow - A freelancer tracks hours across multiple clients using punch-in/punch-out, assigns rates per project, and auto-generates PDF invoices with tax included—all hosted on their own server to ensure client data privacy.
- Managing a distributed development team - A software company with 50+ developers across time zones uses Kimai to log time against Jira tickets, export data to accounting software, and enforce billing policies per customer with custom rates.
- Problem: Manual time logs lead to billing errors → Solution: Kimai’s automated tracking and export - A consultancy loses revenue due to inconsistent time logging. By deploying Kimai, they automate entry via browser extensions and API integrations, reducing invoicing errors by 80%.
- DevOps teams managing microservices across multiple cloud providers - Teams use Kimai’s API to log time spent on incident response, infrastructure updates, or customer support tickets across AWS, Azure, and GCP environments for internal cost allocation.
Under The Hood
Kimai is a feature-rich, open-source time-tracking application built on the Symfony framework that emphasizes API-first development and extensibility. It provides a modular architecture designed for flexibility in managing timesheets, users, and invoicing while maintaining a clean separation of concerns.
Architecture
Kimai follows a monolithic architecture with strong emphasis on modular design and service-oriented principles.
- The application is structured around core domains such as timesheet, user management, and invoicing, each with well-defined boundaries
- Dependency injection and Symfony’s service container are used extensively to manage component interactions and promote testability
- Clear separation between presentation, business logic, and data access layers ensures maintainable code organization
Tech Stack
Kimai leverages a modern PHP ecosystem with Symfony as its core framework and comprehensive tooling for development.
- Built primarily in PHP with Symfony 6.x, Twig templating, and React-based UI components for dynamic interfaces
- Integrates Doctrine ORM for database operations and FOSRestBundle for RESTful API handling, complemented by various frontend libraries
- Employs Webpack Encore for asset compilation, Docker for containerization, and linting tools like ESLint and PHP-CS-Fixer
- Testing is supported through PHPUnit and DAMA\DoctrineTestBundle for isolated database testing in a CI/CD environment
Code Quality
Kimai demonstrates consistent code quality with strong adherence to modern PHP standards and comprehensive test coverage.
- The project includes an extensive test suite covering API behavior and authenticated user workflows, ensuring reliability
- Error handling is implemented through exception-based patterns in both PHP controllers and JavaScript plugins
- Code follows PSR standards, uses modern PHP features like match expressions, and maintains consistent naming conventions
- Some legacy patterns such as deprecated token authentication and mixed JavaScript plugin implementations indicate areas for potential refactoring
What Makes It Unique
Kimai distinguishes itself through its event-driven architecture and extensibility model that enables deep customization.
- Its API-first approach and modular plugin system allow for flexible integration with third-party tools and custom workflows
- The application supports extensive customization through events and hooks, enabling developers to extend core functionality without modifying base code
- Unique in its combination of robust backend services with a modern, extensible frontend architecture