Kimai vs ActivityWatch: Which Is Better for Open-Source Time Tracking in 2026?

Choose Kimai if you need to bill hours. It has timers, per-customer rates, invoicing and multi-user logins, and you can self-host it for free or use Kimai Cloud from €2.99 per user a month billed annually. Choose ActivityWatch for free, automatic, local tracking of apps and windows on Windows, Mac, Linux or Android. Dayflow, our product, suits Mac users who want AI-written timelines.

Kimai and ActivityWatch are both free, open-source time trackers, but they measure different things. Kimai records the time you tell it about, against customers and projects, so you can bill for it. ActivityWatch records what your computer was doing on its own, so you can see where the hours went without starting a timer.

A disclosure first: Dayflow, which appears below as a third option, is our product. It is also free and open source, and it runs only on Macs. This article compares vendor documentation as each vendor published it on October 4, 2026. We cover ActivityWatch against our own app in more depth in ActivityWatch vs Dayflow.

Quick comparison

Tool	Best for	How it tracks	Price	Platforms
Kimai	Freelancers and teams who bill project hours	Manual timers, multi-timer and punch-in/punch-out in a web app	Self-hosted free; Cloud from €2.99 per user a month (annual billing)	Web, self-hosted or Kimai Cloud
ActivityWatch	Private personal analytics across devices	Automatic: active app, window title, away-from-keyboard status, plus browser and editor add-ons	Free	Windows, Mac, Linux, Android
Dayflow (ours)	Mac users who want a readable record of the day	Automatic: one screen frame every 10 seconds, written up by AI as a timeline	$0; optional Pro at $20 a month	macOS 14 or later

Key takeaways

• Kimai is a billing tool. It has timers, per-user, per-customer and per-project rates, invoice templates and a JSON API. It does not track anything automatically.
• ActivityWatch is an observation tool. It logs apps, window titles and idle time by itself and keeps everything on your device. It lists no invoicing and no AI.
• Both are open source. Kimai uses AGPL 3 and ActivityWatch uses MPL-2.0. You can self-host Kimai for free. ActivityWatch is free with no feature gates.
• Kimai has a paid hosted option. ActivityWatch has no hosted option at all. Kimai Cloud is hosted in Germany, according to the vendor. ActivityWatch does not offer device sync yet.
• Dayflow (ours) fills a narrower gap. It turns the day into readable AI summaries, but only on macOS 14 or later, and it has no invoicing or team reports.

What does Kimai do better?

Turning hours into money

Kimai is built around customers, projects and rates. You can set rates per user, per customer or per project. Kimai then produces invoices from configurable templates. For anyone who bills by the hour, that loop from logged time to sent invoice is the whole point, and ActivityWatch does not attempt it.

The timer modes fit different working styles. Multi-timer lets you run more than one clock at once. Punch-in and punch-out mode works more like a time clock for a shift. Tags let you slice entries later without building a new project for every variation.

Working with more than one person

The vendor positions Kimai for freelancers and for companies with dozens or hundreds of users. It supports SAML and LDAP login and two-factor authentication, which matter once IT is involved. It has over 30 translations and a plugin marketplace for features the core does not include.

ActivityWatch describes its users as individuals, and its data stays on each device. There is no shared workspace to invite a colleague into.

Choosing where it runs

Kimai gives you two hosting options. You can self-host it with the official Docker images, on a web server with PHP 8.2 or newer and MariaDB or MySQL. Or you can pay for Kimai Cloud, which the vendor says is hosted in Germany and GDPR compliant. The company is based in Austria. If your clients or employer care where timesheet data lives, that is a clear answer to give them.

Getting data out

Kimai offers data exports and a JSON API. If your accountant, payroll system or a spreadsheet needs the numbers, you are not stuck copying them by hand.

A few features sit behind the Cloud Professional plan: working hour accounts, expenses, custom fields and SSO. Check whether you need any of them before picking the cheaper plan.

What does ActivityWatch do better?

Tracking without your help

ActivityWatch records the active application, the window title and whether you are away from the keyboard, all without you pressing anything. Browser extensions add the active tab title and URL. Editor plugins add coding activity. The record is only as complete as the watchers you install, but none of it relies on you remembering to start a timer.

This is the core weakness of any manual tracker, Kimai included. A timer you forget to start, or leave running over lunch, produces a timesheet that looks precise and is not. ActivityWatch avoids that problem because it records continuously.

Keeping everything local

The vendor states that all ActivityWatch data is stored on your device and is never sent to any server. You have no account, no cloud dashboard and no vendor-side copy to worry about. If your reason for wanting open source is that you do not want activity data leaving your computer, ActivityWatch is the more direct match. Kimai only matches it if you self-host.

The cost of that design is sync. The vendor lists device sync as a work in progress, so a laptop and a desktop keep separate histories today.

Running on more operating systems

ActivityWatch runs on Windows, Mac, Linux and Android. If you split your week between a Linux workstation and a MacBook, one tool can cover both, even without sync. It has no iOS support.

Kimai is a web app, so it also runs on any platform with a browser. That is a different kind of reach. Kimai is available everywhere you have a browser, and ActivityWatch can observe what happens on each of those devices.

Building on top of it

ActivityWatch has a local API and supports custom watchers. A developer can write a watcher for a tool the project does not cover, or pull the raw events into their own analysis. Our roundup of time trackers for developers on Mac covers that use case in more detail.

Costing nothing, permanently

The vendor describes ActivityWatch as completely free and open source, with no feature gates, no usage limits and no ads. The site mentions an optional “AW Pro” patronage, but no price for it was confirmed. If that interests you, see the vendor’s site for current details.

Head-to-head table

Capability	Kimai	ActivityWatch	Dayflow (ours)
Automatic capture	No	Yes: app, window title, away-from-keyboard; tab URL and coding time via add-ons	Yes: one screen frame every 10 seconds
Manual timers	Yes, including multi-timer and punch-in/punch-out	Not listed	No
Invoicing	Yes, with configurable templates	Not listed	No
Multi-user and team use	Yes, with SAML, LDAP and two-factor authentication	Not listed; built for individuals	No team reports
Website blocking	Not listed	Not listed	No
AI summaries	None stated	None listed	Yes, written by local AI, your own provider or Dayflow Pro
Data location	Your server, or Kimai Cloud in Germany	On your device; vendor says it is never sent to a server	Recordings and timeline on your Mac; analysis location depends on mode
Free tier	Self-hosted version is free	Everything is free	Free app at $0
Platforms	Web	Windows, Mac, Linux, Android	macOS 14 or later
Open source license	AGPL 3	MPL-2.0	MIT

A note on the Dayflow data row. Full screen recordings and the timeline are stored on your Mac. With local AI through Ollama or LM Studio, screenshot analysis stays on the device. With your own cloud provider or Dayflow Pro, selected screenshots are processed off the device. Our page on local and cloud processing explains each mode.

Pricing compared

Tool	Plan	Price
Kimai	Self-hosted (open source)	Free
Kimai	Cloud Standard	€2.99 per user a month billed annually, or €3.99 per user a month billed monthly
Kimai	Cloud Professional	€3.99 per user a month billed annually, or €4.99 per user a month billed monthly
ActivityWatch	ActivityWatch	Free
Dayflow (ours)	Free	$0
Dayflow (ours)	Pro	$20 a month

Kimai Cloud prices are in euros and exclude taxes. The pricing page shows two figures per plan without labeling which is which. It also states that annual billing saves 20%, so the lower figure is taken as the annual price here. Kimai Cloud has a 30-day free trial.

What one person pays per year:

• Kimai. If you are willing to run a server, the license costs nothing. Hosting costs depend on your provider, and maintenance takes your time. If you want Kimai Cloud, Cloud Standard is €35.88 a year on annual billing (€2.99 × 12) or €47.88 on monthly billing (€3.99 × 12), before tax. Cloud Professional is €47.88 a year on annual billing or €59.88 on monthly billing.
• ActivityWatch. It costs nothing, with no paid tier required for any feature.
• Dayflow. The app is $0. If you use your own cloud AI provider, that provider’s charges apply. Local AI needs only your own hardware. Dayflow Pro is $240 a year at $20 a month. Details are on our pricing page.

If you bill clients, the real question is not the subscription. It is how many billable hours a forgotten timer costs you. The real hourly rate calculator helps put a number on that for your own work.

When should you choose Kimai?

Pick Kimai when the time you track has to end up on an invoice or a timesheet that someone else reads.

• You bill clients by the hour and want rates and invoices in the same tool as your entries.
• You run a small agency or team and need shared projects, user accounts, SAML or LDAP login and two-factor authentication.
• You want open source and a hosted option. Self-host when you have the skills, or move to Kimai Cloud in Germany when you would rather not run a server.
• You are happy to start and stop timers, or you work in shifts where punch-in and punch-out fits.
• You need a JSON API or exports to feed accounting or payroll.

Freelancers comparing more options should see our guide to time tracking apps for freelancers on Mac.

When should you choose ActivityWatch?

Pick ActivityWatch when you want to understand your own habits rather than bill for them.

• You want tracking that runs without timers and records apps, window titles and idle time automatically.
• You want data to stay on your device, with no account and no vendor server involved.
• You use Windows, Linux or Android as well as a Mac.
• You write code and want editor plugins to log coding activity.
• You like to tinker, and a local API with custom watchers is a feature rather than a chore.
• You want everything free, with no plan comparison to think about.

Where both fall short

Neither tool tells you, in plain words, what you actually did.

Kimai knows what you typed into the description field, and nothing else. A two-hour entry labeled “client work” is still just “client work” a month later. ActivityWatch knows that a code editor, a browser tab and a chat app were in the foreground, with their window titles. That is accurate, but you still have to work out what the session was about. The vendor pages list no AI summaries for either tool.

A second gap is that neither combines automatic capture with billing. Kimai can invoice but cannot see your screen. ActivityWatch can see your apps but cannot invoice. No tool in this comparison does both. A workable setup is to let an automatic tracker capture the day, then enter the billable portion into Kimai, or into a timesheet template if Kimai is more than you need.

Where Dayflow (ours) fits

Dayflow covers the first gap on a Mac. It captures one screen frame every 10 seconds, and AI writes those frames into a readable timeline of the day. You can review that timeline, ask an assistant about it, or export a date range as Markdown from Settings → Export. It is MIT licensed, the app costs $0, and an optional Pro plan costs $20 a month.

Its limits are real:

• It runs only on macOS 14 or later.
• It has no invoicing, payroll, team reports or website blocking.
• AI summaries can miss or misinterpret work, so check them before you share anything built from them.
• It captures more than ActivityWatch does, because it records screen images rather than app names and titles.

If privacy is your reason for choosing open source, read how local and cloud processing works before you pick a mode. Our piece on time tracking without surveillance covers the tradeoffs more broadly.

For the wider field beyond these three, see our roundup of Mac time trackers.

Where Dayflow is the wrong pick

Dayflow is the wrong choice in more cases than it is the right one, so here is where another tool wins:

• You need to send invoices. Kimai wins. Dayflow has no invoicing and no billing rates.
• You manage a team or need shared reports. Kimai wins, with multi-user accounts, SAML, LDAP and two-factor authentication. Dayflow has no team reports.
• You are not on a Mac, or your Mac runs something older than macOS 14. ActivityWatch wins. It runs on Windows, Mac, Linux and Android.
• You want activity data that stays on your device with no setup decisions. ActivityWatch wins. The vendor says its data is never sent to a server. Dayflow can stay local too, but only if you set up local AI through Ollama or LM Studio. Otherwise, selected screenshots go to a cloud provider for analysis.
• You want app names and window titles, not screen images. ActivityWatch wins. It records less, which some people prefer.
• You want website blocking. Dayflow does not offer it, and neither Kimai nor ActivityWatch lists it on the pages checked.
• You want no AI involved at all. ActivityWatch or Kimai wins, since neither lists AI features.

The bottom line

For open-source time tracking, the choice comes down to one question: are you tracking time to bill it, or to understand it?

If you bill it, pick Kimai. It has timers, rates, invoice templates, multi-user logins and a JSON API under AGPL 3. You can self-host it for free or pay for Kimai Cloud from €2.99 per user a month on annual billing.

If you want to understand it, pick ActivityWatch. It tracks apps, windows and idle time automatically across Windows, Mac, Linux and Android, keeps the data on your device, and costs nothing.

If you are on macOS 14 or later and want a written account of your day rather than a list of app names, Dayflow, our own app, is worth a look. It is free and MIT licensed, with an optional Pro plan at $20 a month.

Frequently asked questions

Is Kimai free to use?

The self-hosted version of Kimai is free and open source under AGPL 3. You run it on your own server, which needs a web server, PHP 8.2 or newer and MariaDB or MySQL. Kimai Cloud is paid after a 30-day free trial. Cloud Standard costs €2.99 per user a month on annual billing or €3.99 on monthly billing, and prices exclude taxes.

Does ActivityWatch work on a Mac?

Yes. ActivityWatch runs on Mac, Windows, Linux and Android, and it has no iOS support. It records the active application, the window title and whether you are away from the keyboard. Browser extensions add tab titles and URLs. The vendor states that all data stays on your device and is never sent to a server.

Does Kimai track time automatically?

No. Kimai is a manual project time tracker that runs in a web app. You start and stop timers, use multi-timer or punch-in and punch-out modes, and tag entries against customers and projects. It does not record which apps or websites you use. If you want automatic capture, ActivityWatch or Dayflow covers that job.

Which is better for freelancers who invoice clients, Kimai or Dayflow?

Kimai is the better choice here. It has invoicing with configurable templates, user, customer and project rates, data exports and a JSON API. Dayflow has no invoicing, payroll or team reports. Dayflow can help you remember what you worked on, but Kimai is the tool that turns hours into a bill.

Is ActivityWatch private?

According to the vendor, ActivityWatch stores all data on your own device and never sends it to any server. That also means there is no built-in sync yet, because the vendor lists device sync as work in progress. If you use it on two computers, you have two separate histories for now.

Can ActivityWatch replace a timesheet app like Kimai?

Only partly. ActivityWatch shows which apps, windows and sites were active, and editor plugins add coding time. It lists no invoicing, rates or client billing, so it cannot produce an invoice. Many people would still need a manual or timer-based tool like Kimai to log billable hours against customers and projects.

Can I use Kimai and ActivityWatch together?

You can run both side by side, with ActivityWatch recording activity on your computer and Kimai holding your billable entries. The vendor pages checked list no ready-made connector between them. Kimai has a JSON API and ActivityWatch has a local API, so someone comfortable with scripting could build a bridge, but you would maintain it yourself.

Do Kimai or ActivityWatch have AI summaries?

Neither lists AI features. Kimai's pages state none, and ActivityWatch lists no built-in AI summaries. Dayflow, our product, uses AI to turn screen captures into a readable timeline on macOS 14 or later. You can run that AI locally through Ollama or LM Studio, use your own cloud provider, or use Dayflow Pro.

Does Dayflow run on Windows or Linux?

No. Dayflow is Mac only and requires macOS 14 or later. If you need automatic, open-source tracking on Windows, Linux or Android, ActivityWatch is the option in this comparison that covers those platforms. Kimai runs in a browser, so it works anywhere you can reach its web app, but it does not track automatically.

What is the best open-source time tracker for a Mac?

It depends on the job. Kimai fits if you bill clients and want invoicing, AGPL 3. ActivityWatch fits if you want free, local, automatic app and window tracking, MPL-2.0. Dayflow fits if you want an AI-written timeline of your day on macOS 14 or later, MIT licensed, with an optional Pro plan at $20 a month.