From a freelancer logging billable hours to companies with hundreds of users, Kimai scales professional-grade open-source time tracking - a Symfony/PHP application without the per-seat pricing of Harvest or Toggl. Tracking is flexible by design: run multiple concurrent timers, use punch-in/punch-out mode, or enter times manually, organized by customer, project, and activity with tags, and priced by user-, customer-, or project-specific rates. The billing pipeline is where Kimai earns "professional grade": generate invoices directly from timesheet data with configurable templates (DOCX, ODS, XLSX, PDF), entry grouping, and invoice-number generators, while an export flag locks billed records against editing and excludes them from future invoices - the audit-safety detail spreadsheet workflows never get right. E-invoicing supports EN 16931, XRechnung 3.0, and Zugferd/Factur-X. Enterprise controls come standard: SAML and LDAP login against Google Workspace, Azure AD, or Authentik, TOTP two-factor auth, customizable role permissions, and teams that scope customers and projects to departments. Money and time budgets alert before overruns, advanced reporting slices recorded time by any dimension, and an extensive JSON API plus a plugin marketplace (expenses, approvals, and more) integrate it with existing infrastructure. Over 30 translations, multi-timezone, AGPL-licensed.

With over 1,600 GitHub stars and a design philosophy that fundamentally rethinks how time tracking should work, Traggo abandons the traditional project-task hierarchy that forces your work into rigid categories and instead lets you tag time spans with arbitrary key-value pairs — project:website, type:coding, client:acme, billable:yes — enabling cross-dimensional analysis that conventional trackers cannot replicate. The Go backend compiles into a single binary that runs alongside a SQLite database and embedded web UI in under 10MB total, consuming approximately 50MB of RAM at runtime and starting in seconds on even the smallest VPS. Tags are the fundamental data model: create any tag key with any set of values, then apply multiple tags to each time span simultaneously to track by project, client, task type, energy level, or any other dimension your workflow demands. Customizable dashboards render pie charts, bar charts, and line graphs from tag-aggregated data, letting you visualize time distribution across any combination of dimensions over configurable date ranges. The calendar view displays time spans as colored blocks across days and weeks, while the list view provides chronological entry browsing with inline editing. Multiple themes including light and dark modes adapt the interface to personal preference, and simple user management with role-based access supports small team deployments. Docker deployment runs a single container exposing port 3030 with multi-architecture support for amd64, arm64, and arm v7. Running on a dedicated VPS on RepoCloud with guaranteed CPU, RAM, and SSD, full root SSH access, and a browser serial console. GPL-3.0 licensed.