Kimai vs ActivityWatch vs Tockler: Time Tracking Compared

Time is the one resource you cannot buy back, yet most of us have only a vague idea of where it actually goes. The open source world offers three very different answers to that question. Kimai is a server-based, project-oriented time tracker built for teams and invoicing. ActivityWatch is an automatic, local-first tracker that watches which apps and websites you use. Tockler is a lightweight desktop-only automatic tracker that quietly builds a searchable timeline of your day. They overlap on the surface, but they solve different problems — the right pick depends entirely on whether you need billable hours or personal awareness.

Kimai — Project Time Tracking for Teams

Kimai is the heavyweight of the three: a full time tracking platform, made in Austria, aimed at project-driven teams and businesses. It runs as a web application you can self-host (Docker or manual install) or rent as a managed Kimai Cloud, and it is built around customer/project/activity hierarchies so every recorded hour can be tied to real work and invoices.

What sets Kimai apart is that it is about structured, billable time, not just “where did my day go”. It ships with configurable invoice templates that export to PDF or DOCX, a powerful reporting layer, tags, a JSON REST API for integrations, and enterprise touches such as LDAP/SAML login and TOTP two-factor authentication. Teams that need to charge clients, monitor capacity and keep an auditable record of hours will get the most from it.

The catch: unlike the other two, Kimai does not track your activity automatically. You start and stop timers, or log entries yourself, so the accuracy depends on your discipline. It is also more to run — practically speaking a self-hosted server, not a simple desktop app. Licenced under the GNU AGPL v3.

Kimai Strengths

• Invoice-ready — configurable templates export timesheets directly to PDF or DOCX.
• Great reporting — slice recorded time by user, customer, project, activity, tag or period.
• Team-scale — multi-user with LDAP/SAML login and TOTP 2FA.
• Extensible — JSON API and a plugin marketplace.
• Cloud or self-hosted — full data ownership when self-hosted, GDPR-compliant EU hosting on Kimai Cloud.

ActivityWatch — Automatic, Local-First Habit Tracking

ActivityWatch takes the opposite approach. It is an automated tracker that runs on your device and watches which applications and window titles are active, plus optional browser extensions for Chrome and Firefox and editor plugins for coding time. Everything is stored locally and never uploaded to the cloud, so you get RescueTime-style insight without the privacy trade-off.

Its real strengths are breadth and open data. ActivityWatch runs on Windows, macOS, Linux and Android, tracks browser tabs and code editors, and lets you break activity down into categories for a clearer productivity picture. Because it is open source with a local database, you can query your own raw activity data directly rather than relying on a vendor’s dashboard. It is the best choice if you want automatic, low-effort insight into your digital habits.

The catch: ActivityWatch tells you what you did, not what work it was for. It has no invoicing or client/project reporting, so it is not a billing tool out of the box. Licenced under the Mozilla Public License 2.0.

ActivityWatch Strengths

• Fully automatic — watches the active app and window title with no manual timers.
• Cross-platform — Windows, macOS, Linux and Android.
• Local & private — data never leaves your device unless you choose to sync it.
• Browser & editor support — Chrome/Firefox extensions and code-editor watchers.
• Open raw data — query your own activity database directly.

Tockler — Simple, Private Desktop Timeline

Tockler is the lightest of the three: a free, open-source Electron desktop app that automatically records the active window title and idle time, then turns that into an interactive, zoomable timeline of your day. It is fully local — no account, no cloud — and focused squarely on the individual rather than teams.

Its appeal is simplicity and honesty. You install it, it quietly builds a searchable, exportable record of which apps you used and for how long, and it comes with usage analytics and trends. It is a great fit for freelancers or students who want automatic self-awareness without the overhead of a server or a subscription. As the listing notes, it pairs well with a manual, project-oriented tracker like Kimai when you need accurate billable time on top of an activity log.

The catch: Tockler is desktop-only (Windows, macOS, Linux, Electron) with no multi-user, no browser-tab tracking, and no invoicing. Licenced under the GPL-2.0.

Tockler Strengths

• Set-and-forget — records active window titles and app usage automatically.
• Interactive timeline — zoomable, searchable history of your day.
• Usage analytics — online time, app patterns and trends.
• Fully private — all data stays on your device; no account required.
• Dead simple — a desktop app, nothing to self-host.

How to Choose

If your goal is billable, invoice-ready time for a team or consultancy, pick Kimai. If you want automatic insight into your digital habits across every device you own, pick ActivityWatch. If you want a simple, private desktop timeline with nothing to host, pick Tockler. And there is nothing stopping you running an automatic tracker alongside Kimai — many people do, pairing the honesty of ActivityWatch or Tockler’s timeline with the structure of Kimai’s projects and invoices.

All three are free and open source, so there is no licence cost to try each for a week on your own data and see which one actually changes how you spend your day. Read the full details on the Kimai, ActivityWatch and Tockler listings, or browse hundreds more free and open source tools in the directory. Know a great time tracking tool we are missing? Suggest it.