A plain timer: count down to zero, or count up with laps. It survives a reload, and needs no account and no connection.
00:05:00
Ready
Space starts or pauses · L takes a lap · R resets
Laps
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Sessions
nothing yet
Nothing yet. Every timer you finish shows up here.
The clock is system time, not a frame counter. Remaining time is computed from an absolute timestamp, so switching tabs, locking the phone or reloading the page doesn't make it drift — come back and the number is already where it should be. If the tab is in the background the browser may hold the alert up to a second late; the time shown is still exact.
A countdown and a stopwatch do different jobs. The countdown sets the limit before you start, which is what you want to box in a task that tends to sprawl. The stopwatch makes no judgement: it just measures how long something actually took, which is what you need when you're trying to calibrate your estimates rather than meet them.
Nothing leaves this device. Sessions and the running timer are kept in this browser and disappear when you clear them. There's no server, no account and no push notification — close the tab and the alert goes with it.