kimai/kimai — Kimai is the #1 open-source time-tracking application.

Description and use

**Brief Summary**
Kimai is a leading open‑source, web‑based time‑tracking platform that lets freelancers, teams, and enterprises log work hours, generate detailed reports, and create invoices. It is available both as a self‑hosted (On‑Premise) solution and as a SaaS offering, and is built in PHP with an active community (4,641 ★, 775 forks).

**Value**
Kimai provides a ready‑made foundation for any product that needs to capture billable time, calculate charges, or issue invoices, dramatically shortening the time to integrate monetisation, billing, or PSP (payment‑service‑provider) flows. Its flexible API and extensible plugin architecture let you plug in custom pricing rules, tax calculations, or third‑party payment gateways without building a time‑tracking system from scratch.

**Practical Adoption Path**

1. **Proof‑of‑Concept** – Clone the repo, run the Docker compose setup, and verify basic timesheet creation and report generation.
2. **Integration Exploration** – Review the README and API docs; implement a small connector that pushes logged hours to your billing engine or payment gateway.
3. **Pilot** – Deploy the on‑premise instance in a staging environment, enable the required plugins (e.g., invoicing, export), and run a limited user group through the end‑to‑end billing flow.
4. **Scale** – Harden the deployment (HTTPS, DB backups, CI/CD), add custom plugins or webhooks for your PSP, and migrate to production.

**Production Readiness**
Kimai scores high on production readiness: recent commits (as of 2026‑05‑12), a large and active community, and proven use in many organisations. Its PHP codebase is mature, and the Docker images simplify secure, reproducible deployments. The primary risk lies in the integration surface—metadata does not expose a turnkey billing API—so teams should allocate time for initial setup and validation before committing to a full rollout.

Problem

kimai/kimai helps integrate monetization, billing, or PSP flows faster.

Outcome

High for an OSS candidate: recent activity, adoption, and ecosystem signals are strong enough for a serious pilot.

Workflow

• integrate billing or checkout
• evaluate PSP flows
• automate payment operations

Evidence

Kimai is the #1 open-source time-tracking application. From freelancers to companies and organisations - everyone can manage timesheets, generate reports, create invoices and so much more... Web-based multi-user application, available as On-Premise or SaaS version: https://www.kimai.org

Source