Reliability Guide
What browser timers and alarms can do, and what they cannot promise.
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What Clockfresh does for accuracy
Timers and alarms are based on target timestamps, not accumulated interval ticks. If a browser throttles background JavaScript, the display catches up from the real clock when it runs again.
What still depends on the browser
- Audio needs a user gesture before the browser allows sound.
- Selected timer and alarm sounds repeat until dismissed, with a 3-minute automatic stop.
- Notifications require permission and device/browser support.
- Wake lock support varies by browser, battery mode and operating system.
- Closing the tab or quitting the browser stops page JavaScript.
- Offline support depends on the route being cached before the connection drops.
Best setup for important alarms
- Start the alarm from the device you will keep nearby.
- Allow sound and notifications when prompted.
- Keep the tab or installed web app open.
- Use a native device alarm as backup for critical wake-ups.
Related tools
Alarm clock Timer PWA device QA Dashboard
Questions
- Will an online alarm work if I close the tab?
- No. A browser alarm needs the page or installed web app to stay available. Closing the tab stops page JavaScript.
- Why do I need to press start before sound works?
- Browsers block autoplay. Clockfresh unlocks audio from your explicit start or set-alarm gesture.
- How long do timer and alarm sounds play?
- Finish alerts repeat until you dismiss them with the visible stop/reset/snooze control. If nobody returns to the device, Clockfresh stops the sound automatically after 3 minutes.
- Does offline mode mean every page works forever?
- No. The service worker caches the app shell and selected routes. Production device testing still matters.
- Does wake lock work everywhere?
- No. Wake lock support varies by browser and device. Clockfresh requests it where available and keeps timing based on absolute clock time.