Kimai

Overview

Kimai is an open-source time tracking system from Germany. The project was first initiated in 2006, and the v2 version, led by Kevin Papst, was fully rewritten with the PHP + Symfony framework. Kimai is open source under AGPLv3, so users can freely obtain the full source code and self-host it on their own servers with no limits on users or projects. With the combination of "open source + self-hosting + complete billing capabilities," Kimai has become a representative choice in time tracking for teams that value data sovereignty and cost control.

Within the productivity space, Kimai covers time recording, project and customer accounting, expense tracking, invoice export, team and permission management, and offers a complete REST API with a 20+ language interface. Data is hosted on the user's own server, naturally meeting GDPR requirements, and it is especially popular among European freelancers, agencies, and SMBs. See remote team management comparison for its position among timing tools.

Key Strengths

• Fully open source with zero license fees: AGPLv3 licensed with complete public source, no per-seat subscription fees, so long-term cost is only server expenses, friendly to budget-conscious teams. See open source software market.
• Full data self-hosting: Hosted on your own server with controllable data sovereignty and privacy, meeting GDPR requirements; check GDPR compliance checklist.
• Multi-level accounting: Multi-level organization across projects, customers, activities, and tasks with rate-based automatic revenue and margin calculation for clear client billing. Combined with automated invoicing systems, it forms a complete loop.
• Built-in billing: Expense tracking plus per-customer PDF invoice generation, avoiding extra billing tool purchases.
• Extensible and integrable: Complete REST API, 2FA, LDAP/SSO, and plugin support for deep integration into existing team toolchains.

Product Ecosystem

Time Recording

One-click timers plus manual entry on the web organize hours by project, customer, activity, and task, writing data into timesheets in real time.

Timesheets & Accounting

Weekly/monthly member hour summaries with approval flows; combined with rates to compute amounts and margins for project settlement.

Expenses & Invoices

Record project spending and attribute it to customers, then generate per-customer PDF invoices from hours and expenses to close the billing loop.

Teams & Permissions

Multi-team and multi-member management with fine-grained permissions and 2FA for secure team and agency scenarios.

Plugins & API

A plugin marketplace with official and community extensions, and a REST API for integration with PM, CRM, and accounting systems; see remote team toolchain selection.

Limitations

• Deployment and maintenance barrier: No free official cloud hosting, requiring you to set up and maintain a PHP/Symfony environment, with a higher barrier for non-technical users.
• Experience lags commercial SaaS: Interface and interaction depth lag products like Toggl Track and Clockify, and mobile is a responsive web app rather than native, with average experience.
• Scarce Chinese resources: Documentation and community are mainly English; Chinese tutorials and Q&A are limited, so troubleshooting relies on English material and GitHub.
• Limited feature depth: Budget control and deep reporting lag large commercial platforms; large teams should evaluate sufficiency, see productivity tool comparison.

Use Cases

• Data-sovereignty-focused teams (★★★★★): Self-hosting plus GDPR, data fully under your control.
• Client-billing freelancers and agencies (★★★★★): Multi-customer accounting plus PDF invoices, complete billing loop.
• Budget-sensitive SMBs （★★★★☆）: Open source and free, only server costs, low long-term ownership cost.
• Out-of-the-box users （★★☆☆☆）: Deployment and maintenance cost is high; consider commercial SaaS, see freelance work management tips.
• Large enterprises （★★★☆☆）: Self-build and customization possible, but deep reporting and compliance need in-house effort.

Pricing

Note: Self-hosting only incurs server and maintenance costs; official cloud hosting targets teams that do not want to manage infrastructure, with prices as public reference values.

FAQ

• Is Kimai free? Yes. Kimai is fully open source under AGPLv3 and free to use and modify; the official cloud hosting service is an optional paid item; for open-source options see open source software market.

• Does Kimai require self-deployment? You can self-host on your own server or subscribe to official cloud hosting (kimai.cloud) to avoid operations, choosing either as needed; for data sovereignty and compliance see GDPR compliance checklist.

• How do I choose between Kimai, Toggl Track, and Clockify? Kimai stands out for open source self-hosting and data sovereignty, suiting privacy- and cost-conscious teams; Toggl Track and Clockify offer managed cloud services with larger free tiers, see productivity tool comparison.

• Does Kimai support invoicing? Yes. You can record expenses and generate per-customer PDF invoices from hours, with amounts calculated by rates; see automated invoicing systems.

• Is Kimai data secure? Data is hosted on your own server and does not pass through third parties, naturally meeting GDPR; 2FA and fine-grained permissions can further enhance security; for compliance requirements see GDPR compliance checklist.