ZenTabTimer

At a glance

ZenTabTimer is worth a look if you want a session timer you can glance at while working in another browser tab. Its favicon is a shrinking pie, while the tab title stays ZenTabTimer. The entire implementation is one HTML file with no backend or build step. That simplicity is the attraction, but this is a lightweight timer to evaluate in your browser, not a dependable system alarm.

Good fit

Someone who wants a rough visual sense of time remaining without switching back to a countdown page. The source offers preset durations from five to 120 minutes and a custom-minute field. Each update redraws a small canvas as the favicon, so the cue lives beside the tab name. It is a useful design if your browser keeps that tab visible; it loses its advantage when tabs or favicons are hidden.

Consider something else when

You need scheduled work/break cycles, pause/resume, synchronized history or an alarm that must fire while the browser sleeps. The current file starts one countdown at a time, and starting another replaces it. Timer state lives in page variables rather than saved session storage, so reloading loses the running countdown. The intended workflow is Chrome; support across arbitrary browsers is not established.

Start here

The README’s intended path is to open timer.html in Chrome, pin the tab and choose a preset or enter a positive whole number of minutes. The page status shows time remaining and the favicon drains as the deadline approaches. Starting a timer can request notification permission; the optional notification is separate from the generated completion sound. The README suggests serving the file locally if file-URL notifications do not work. No timer, sound or notification was exercised for this source-based assessment.

Cost and requirements

The inspected repository contains the README and a self-contained HTML file, without a package install or server dependency for the file-opening path. Its script uses browser canvas, audio and optional Notification APIs, with no external script, fetch or backend call in that file. That describes this implementation, not a browser-wide privacy guarantee. The README offers informal reuse permission, but the acquired tree has no separate named license file; check the permission you need before incorporating it into another project.

Limits to know

The timer computes remaining time from a deadline, which avoids treating every delayed background tick as elapsed time of exactly one second. Focus, visibility and page-show listeners let it catch up when the page wakes. They do not guarantee an on-time sound or notification during sleep, tab suspension or discard. Pinning is the author’s recommendation, not a verified cure for those conditions. No browser timing, favicon visibility, audio or notification delivery was tested.

Still unclear

• Actual background-tab and sleep/wake alert delivery were not tested.