Kimai

Self-hosted time tracking, honestly reviewed. No marketing copy, just what you get when you run it yourself.

TL;DR

• What it is: Open-source (AGPL-3.0) time tracking application — think Toggl or Harvest, but the server is yours and the developer is one person in Vienna, not a VC-backed SaaS company [2].
• Who it’s for: Freelancers, agencies, and small-to-medium companies who track billable hours and need to generate invoices from those timesheets, without paying per-seat SaaS fees [1][2].
• Cost savings: Paid time tracking SaaS (Toggl Track, Harvest) charges $8–$14/seat/month. Kimai self-hosted runs on a $5–10/mo VPS with unlimited users [2].
• Key strength: The feature-to-complexity ratio is unusually good. You get invoicing, reporting, multi-user, LDAP/SAML, 2FA, and a JSON API in a tool that multiple reviewers describe as “clean and straightforward” [3][4].
• Key weakness: AGPL-3.0 license (not MIT) and single-maintainer project. Kevin Papst has been building this since 2009 — the bus factor is one [2].

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What is Kimai

Kimai is a web-based time tracking application. You log time against customers and projects, generate reports, and produce invoices — all from a browser, including on mobile. The tagline is “time tracking for project-driven teams,” which is accurate. It’s aimed squarely at the billing workflow: log time → analyze → invoice client.

The project has been running since 2006, which is ancient by open-source standards. The current version (Kimai 2) was rewritten from scratch and released in 2018. Kevin Papst, a developer based in Vienna, took over maintenance in 2009 and has been the sole maintainer since. In 2023, Kimai became his full-time job [2]. That’s both a positive signal (the project pays its own bills) and a risk to understand clearly (one person, no team).

The GitHub repository sits at 4,566 stars. The website claims over 5,000 paying customers across the cloud and self-hosted support plans [homepage]. One review from a German agency notes 16 years of continuous use — the longevity is real [3].

It’s available in two forms: self-hosted (free, AGPL-3.0) or Kimai Cloud (paid SaaS hosted in Germany). The software is European by design — built in Austria, hosted in Germany, with explicit emphasis on data protection and GDPR compliance [homepage]. For EU-based businesses or anyone operating under GDPR, that framing matters more than it does in a US context.

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Why people choose it

The reviews cluster around two overlapping reasons: cost and control, and the invoicing workflow.

Cost and control. A TYPO3 agency (Pagemachine AG) specifically cited this when they switched from Toggl: “As a TYPO3 agency, open source, data sovereignty, and full control over the software were essential to us. We wanted to decide ourselves when to enable specific features and have the freedom to implement our own customizations.” [3]. This is the pattern — agencies and professional services companies who treat time tracking as a core business function, not a convenience, and don’t want a SaaS vendor deciding what they can configure.

The migration from Toggl they described was smooth, and “our team quickly adapted to the interface, which resembles Toggl but offers more advanced options — especially for reporting and analytics” [3]. That’s a useful calibration point: Toggl-like simplicity for day-to-day use, deeper reporting and invoicing when you need to bill.

The invoicing workflow. Multiple reviewers land on this specifically. Isaac Mailach, a studio musician: “I love how I can combine time tracking, expense tracking, and invoicing into one app without features hidden behind nagging subscriptions. I can click one button to invoice my clients now! Seriously a godsend.” [3]. This isn’t a feature that gets enough credit in comparisons — most time tracking SaaS tools make invoicing a premium tier or push you to integrate with a separate accounting tool. Kimai handles it natively, from the same interface where you log time.

Support quality. An unusual number of reviews specifically call out support responsiveness, which is notable for an open-source tool. Jasmin (software developer): “the biggest plus is the support: the team responds quickly and addresses all requests and concerns, even when a special solution is needed.” [3]. Panagiotis Ntinis: “They responded quickly and had my issue resolved within half an hour, saving me from a potential disaster.” [homepage]. Given the project is one person, this is either Kevin being unusually responsive or a filtered sample. The support page is transparent about the model: email support and video calls for paying customers, GitHub community for free self-hosted installs [1].

Longevity as a signal. The consistent theme across the older reviews is people describing 5, 10, even 16 years of use. That’s not typical for open-source software. Armin Bittner (a business owner): “Die beste Software für die Projektzeiterfassung für Freelancer und kleine Unternehmen. Seit 16 Jahren im Einsatz bei uns” — that’s 16 years in continuous use [3]. Longevity doesn’t mean the software is good, but it does mean the user’s dependency on it hasn’t been broken by churn, pivots, or feature removal.

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Features

From the README and website, the feature set is broader than most self-hosted alternatives:

Time tracking:

• Multi-timer and punch-in/punch-out mode [README]
• Runs in browser on any device, including mobile [2][homepage]
• Tagging system for granular filtering [README]
• Multi-timezone, multi-language (30+ translations) [README]

Project and customer management:

• Unlimited users, customers, projects, time entries [2][README]
• Teams with scoped data access (assign customers/projects to teams) [homepage]
• User-, customer-, and project-specific billing rates [README]
• Money and time budgets per project [README]

Reporting and invoicing:

• Reports by user, customer, project, activity, tag, and time period [homepage]
• Configurable invoice templates (PDF, DOCX) [homepage][README]
• Customizable invoice numbers and entry grouping [homepage]
• Data export in multiple formats [README]

Authentication and security:

• LDAP and SAML login (Google Workspace, Azure AD, Authentik) [README][homepage]
• Two-factor authentication via TOTP [README][homepage]
• Customizable role and team permissions [README]
• SSO — included in the self-hosted version [merged profile]

Developer access:

• Extensive JSON API for reading and writing data [README][homepage]
• Plugin system with documented extension points [README][homepage]
• Active plugin marketplace at kimai.org/store/ [README]
• Steven Broos (freelance system engineer) mentions using the API to automatically start/stop timers when arriving at a client site via geolocation [3]

Deployment:

• Docker images (FPM only or with Apache) [README]
• Docker Compose with documented Hetzner and DigitalOcean guides [README]
• Synology NAS support [README]
• Git + Composer setup for direct server installs [README]

The SSO inclusion in the self-hosted community edition is worth highlighting — in Activepieces and n8n, SSO is gated behind commercial licensing. Kimai includes it free.

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Pricing: SaaS vs self-hosted math

Kimai Cloud (their SaaS): Pricing tiers are not fully detailed in the provided sources. The website mentions a free trial and references subscription plans, with features like custom fields, task planning, expense management, audit trail logs, and vacation/sickness tracking on paid tiers [homepage]. Exact Cloud pricing is not available from the scraped data — check kimai.org directly for current numbers.

Self-hosted (free):

• Software: $0 (AGPL-3.0)
• VPS: $5–10/month (Hetzner, Contabo, DigitalOcean)
• Unlimited users, unlimited customers, unlimited time entries
• Professional support plan (installation, updates, video calls) available directly from Kevin at quoted hourly rates [1]

Support pricing from the support page [1]:

• Updates: roughly 30–60 minutes of developer time
• Migration from Kimai v1: ~2 hours
• Fresh installation: 1–2 hours depending on setup/host

Toggl Track for comparison:

• Free: unlimited time tracking, 3 projects
• Starter: ~$9/seat/month (unlimited projects, billing rates)
• Premium: ~$18/seat/month (advanced features)
• A 5-person team on Toggl Starter runs ~$45/month, $540/year

Harvest for comparison:

• Free: 1 seat, 2 projects
• Pro: $12/seat/month (unlimited)
• Same 5-person team: $60/month, $720/year

Clockify for comparison:

• Kimai’s most direct competitor in the self-hosted space; Clockify offers a generous free tier on their SaaS but self-hosting is a paid plan.

Self-hosted Kimai math: 5-person team, Hetzner VPS at $6/month, unlimited users and projects = $72/year vs $540–$720/year for comparable SaaS. Over three years: ~$216 vs $1,620–$2,160. The savings are real, and they compound — the self-hosted cost is flat, the SaaS cost grows with headcount.

For a 20-person agency, that math becomes extreme. Toggl Premium for 20 seats is ~$360/month. Kimai on the same $6 VPS is still $6/month.

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Deployment reality check

Kimai has official documentation for Hetzner and DigitalOcean deploys using Docker Compose and Caddy [README]. The supported paths are well-documented, which is a real operational advantage over tools where deployment is basically “figure it out from the GitHub issues.”

Requirements:

• PHP 8.1.3+ (8.2, 8.3, 8.4, 8.5 supported) [README]
• MariaDB ≥ 10.6 or MySQL ≥ 8.4 [README]
• A webserver and subdomain (subdirectory installs are not supported) [README]
• PHP extensions: gd, intl, json, mbstring, pdo, tokenizer, xml, xsl, zip [README]
• For HTTPS: reverse proxy (Caddy recommended in official docs)

The subdomain-only constraint is worth noting for anyone trying to run this at mysite.com/kimai — it won’t work. You need kimai.mysite.com or a dedicated domain.

What can go sideways:

• PHP dependencies can cause version conflicts on shared hosting or older VPS images. Budget time to verify your PHP setup matches requirements.
• The support page notes that installations on unfamiliar server setups can cause problems for users not familiar with server systems [1]. This is honest disclosure, not marketing. If you’ve never configured a reverse proxy, budget extra time.
• The “subdirectory not supported” constraint is a common gotcha — it rules out some shared hosting configurations entirely.
• Plugin compatibility: as with any plugin ecosystem, not all plugins are maintained at the same pace as the core. The marketplace exists at kimai.org/store/ but quality varies [README].

Realistic time estimates from the support page [1]:

• Fresh install by the Kimai developer (paid): 1–2 hours
• Updates: 30–60 minutes
• Migration from Kimai v1: ~2 hours

For a self-reliant technical user following the Docker Compose docs: 30–90 minutes on a fresh VPS. For a non-technical founder with no prior Linux server experience: hire Kevin to do it, or budget a full afternoon and expect troubleshooting.

The Synology NAS support is a real differentiator for small offices that already have a NAS on the network and don’t want to pay for a VPS [README].

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Pros and Cons

Pros

• SSO included in self-hosted. LDAP and SAML are not paywalled behind a commercial license — they’re part of the free installation [README][homepage]. This matters when your team already uses Google Workspace or Azure AD.
• Invoicing is native. Generate PDFs directly from timesheets, with configurable templates and invoice numbering [README][homepage]. No integration required with a separate billing tool.
• Genuinely long-lived project. Kimai has existed since 2006 and is in active development today. The codebase has real depth and the developer has real incentive to keep it going since it’s now his primary income [2].
• EU-based, GDPR-native. Built in Austria, hosted in Germany. For European businesses, this simplifies compliance conversations [homepage].
• JSON API. External integrations, CLI timer starts, API-triggered logging — the API is described as “extensive” and there are documented real-world uses [README][homepage][3].
• Multi-user with role permissions at no extra cost. Unlimited users, customizable per-team data access, without tier gating [2][README].
• 30+ language translations. Active community-maintained through Weblate [README].
• Strong community reviews. The review page [3] shows consistent, specific, multi-year testimonials — not the typical “great product!” filler.

Cons

• AGPL-3.0 license. Not MIT. If you plan to integrate Kimai into your own product or deploy it for clients as a white-label solution, AGPL requires you to open-source the modifications. This is a meaningful restriction that the MIT-licensed alternatives don’t impose [merged profile].
• Single maintainer. Kevin Papst is Kimai. This is the central risk of the platform — no engineering team, no organizational backup, no clear succession plan. The project is healthy now; that can change [2].
• PHP stack. Kimai runs on PHP + Symfony. In a world increasingly dominated by Node, Go, and Python tooling, this limits who can contribute patches or customizations. PHP hosting is cheap and ubiquitous, but developer familiarity is uneven.
• Subdirectory install not supported. You need a subdomain. Minor, but it eliminates some hosting configurations [README].
• Plugin quality varies. The marketplace has paid and free plugins, but there’s no centralized vetting of maintainer activity [README]. A plugin that worked last year may not be maintained today.
• Pricing transparency. The Cloud pricing isn’t clearly published in a way that lets you compare plans without contacting sales or visiting the current site. Self-hosted support pricing requires emailing Kevin directly [1].
• No mobile app. Kimai is browser-based with responsive design. It works on mobile, but there’s no native iOS or Android app with offline support or widget-based timer controls [README][homepage].

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Who should use this / who shouldn’t

Use Kimai if:

• You’re a freelancer or agency billing clients by the hour and you need timesheets that turn directly into invoices — without paying $12/seat/month.
• Your team is already on Google Workspace or Azure AD and you want SSO without buying a commercial license.
• You’re an EU-based company where data residency and GDPR compliance matter.
• You have, or can hire, someone comfortable with Docker and a Linux server for initial setup.
• You want a tool that will likely still exist and receive security patches in 10 years.

Skip it if:

• You’re planning to embed Kimai in a product you ship to clients. AGPL requires you to open-source your modifications — pick a differently-licensed tool if this matters [merged profile].
• Your team is non-technical and has no one who can manage a VPS. The cloud option exists, but pricing isn’t self-serve in a way that makes it obvious for small teams.
• You want a native mobile app with offline timer support. Kimai’s mobile experience is a responsive web app, not a dedicated app.
• You need AI-powered features, “smart” categorization, or integrations with 500+ tools. Kimai is focused on the time-tracking and billing workflow — it doesn’t try to be a general business automation platform.

Stay on Toggl/Clockify if:

• You have fewer than 5 users and the free tier covers you.
• You use the mobile app constantly and need offline mode.
• No one on your team has touched a Linux server.

Consider Clockify self-hosted if:

• You need a more polished SaaS-grade UI and are willing to pay for their self-hosted plan.
• You need the native mobile apps.

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Alternatives worth considering

• Toggl Track — the most direct SaaS comparison. Better mobile experience, large integration catalog, per-seat pricing that gets expensive fast. Closed source, US-hosted.
• Clockify — freemium SaaS with a self-hosted paid option. More polished UI than Kimai for casual users, but self-hosting is gated behind payment, and the feature depth for invoicing is weaker.
• Harvest — popular in agencies for its Harvest + Forecast combination. Per-seat pricing, excellent integrations, no self-hosting option, US-hosted.
• Timetagger — open-source, MIT-licensed, much simpler than Kimai. Good for solo freelancers; doesn’t handle multi-user or invoicing at Kimai’s depth.
• Traggo — open-source time tracker with a tag-only model. Interesting for developers who want a minimal setup, but not suitable for billing workflows.
• ERPNext / Frappe — if you’re already considering ERPNext for project management, it has time tracking built in. Overkill if you only need time tracking, relevant if you need the full ERP picture.

For a freelancer or agency focused on billing, the realistic shortlist is Kimai vs Toggl Track. Pick Kimai if data control and cost matter. Pick Toggl if mobile experience and setup simplicity matter more than the monthly bill.

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Bottom line

Kimai is the right answer for a specific, well-defined problem: a team that bills by the hour, generates invoices from timesheets, and doesn’t want to pay per-seat SaaS fees forever. It doesn’t oversell itself. The website says “time tracking for project-driven teams” and that’s exactly what it is — no AI buzzwords, no “platform” ambitions, no gamification. Just a well-maintained time tracking and invoicing tool that’s been running reliably for nearly two decades.

The single-maintainer reality is the honest risk to weigh. Kevin has been building this since 2009, it became his full-time job in 2023, and the community is active — but one person is still one person. If that’s acceptable (and for a self-hosted installation where you control the code, it often is), the trade-off is worth it: enterprise features like SSO and LDAP at zero license cost, unlimited users, and invoicing in the same tool where you log time.

If paying $12/seat/month for Toggl or Harvest is fine, stay on them. If you’re an agency watching that bill grow every time you add a contractor, Kimai on a $6 VPS is the cleaner math.

If deployment is the blocker, that’s exactly what upready.dev handles — one-time setup, you own the infrastructure.

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Sources

1. Kimai Support Page — https://www.kimai.org/en/support.html
2. About Kimai — Project History and Maintainer — https://www.kimai.org/en/about.html
3. Kimai User Reviews — https://www.kimai.org/en/reviews
4. Kimai Open Source Community Page — https://www.kimai.org/en/open-source-community

Primary sources:

• GitHub repository: https://github.com/kimai/kimai (4,566 stars, AGPL-3.0)
• Official website: https://www.kimai.org
• Plugin marketplace: https://www.kimai.org/store/
• Documentation: https://www.kimai.org/documentation/