Why it's a strong pick

Tomato Clock is open source under GPL-3.0, and its code is public on GitHub. We could read the source and confirm its four permissions and Manifest V3 build. The trade-off: it is a timer only, with no task list and no site blocking.

What it does

Tomato Clock splits work into 25-minute "Tomato" intervals with short breaks between them, and a long break after four. The README says you can change the lengths. It sends browser notifications with sounds you can change, tracks stats, and lets you pause and resume. There is also a dark theme.

Key features

Tomato intervals. 25-minute work blocks, short breaks, and a long break after four.
Custom lengths. The README says interval lengths are customizable.
Notifications. Browser notifications with customizable sounds tell you when a Tomato or break ends.
Stats. It tracks your completed Tomatoes. The README says stats sync across devices through your browser's cloud storage.
Pause and resume. Stop a running interval and pick it up again.
Dark theme. Built in.
Open source. GPL-3.0, maintained by samueljun on GitHub. It is also on Firefox Add-ons and Microsoft Edge Add-ons.

Who it's for

Tomato Clock is for people who want a timer and nothing else competing for attention. It also suits anyone who likes to read the source before installing. If you want tasks next to the timer, pick Focus To-Do. If you want site blocking, see Pomofocus or LeechBlock NG. Its closest rival is Marinara. Compare them on our Marinara alternatives page.

What permissions does Tomato Clock ask for?

Four, according to the build config in its GitHub repo: notifications, storage, alarms and offscreen. It is a Manifest V3 build with a service worker. The install prompt in Chrome shows the final list. The code is open source under GPL-3.0, so you can read the manifest yourself.

Is Tomato Clock open source?

Yes. The README says it is released under GPL-3.0, and the maintainer is samueljun on GitHub. The code is public, so you can read how it works. It is also listed on Firefox Add-ons and Microsoft Edge Add-ons. We did not audit the code line by line, and open source alone does not prove how it treats your data.

Does Tomato Clock need an account?

The README describes no sign-in, so it appears not to need one. We did not test a fresh install, so check the first-run screen. Stats sync works through your browser's cloud storage, so it needs browser sync turned on if you want stats on more than one device.

What does Tomato Clock do with my data?

We could not read the developer's privacy policy when we checked; read it before installing. The GitHub repo had no privacy file when we looked. The README says stats sync through your browser's cloud storage, and the permissions list includes storage.

FAQ

Is Tomato Clock free? The README shows no price. It has a Buy Me a Coffee link for donations.

Can it block websites? No. It has no site blocking, by design. See LeechBlock NG for that.

Does it have a task list? No. It counts completed Tomatoes. For tasks, see Focus To-Do.

Good to know

Stats sync depends on your browser's cloud storage. If browser sync is off, expect your stats on one device only. The timer itself does not need sync.

Other productivity timers to compare

Tomato Clock is one of 6 picks in our productivity timers guide:

Marinara: A plain Pomodoro timer in your toolbar. Set your own interval lengths. Open source under MIT.
Focus To-Do: A Pomodoro timer and a to-do list in one extension. It works offline without an account. Sync needs one.
Pomofocus: A Chrome listing that pairs a Pomodoro timer with a task manager and a website blocker. Check the publisher name before you install.
Forest: A focus timer that grows a virtual tree. Leave a session early and the tree dies.
ActivityWatch Web Watcher: An open-source extension that logs your browser activity for the ActivityWatch time tracker.

See alternatives: Marinara alternatives lists Tomato Clock as the simple option.

Also see: Best Chrome extensions for students · Best Chrome extensions for remote work