Online Alarm Clock
Set a time, leave the tab open, get woken up.
Runs entirely in your browser
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⏰ Alarm
Set a wall-clock time and the page counts down to it, rolling over to tomorrow if the time has already passed today. The alarm is generated by the browser's audio engine, so there is no sound file to download and nothing to load when it fires.
Keep the tab open. A browser cannot wake a device up or fire an alarm after the page is closed. For a phone alarm that survives a locked screen, use the phone's own clock app.
How to use it
- Pick the time you want the alarm to go off.
- Press Set, and the countdown and the target time appear.
- Leave the tab open. Press Stop when the alarm rings.
Questions
Will the alarm work if I close the tab?
No. The countdown lives in the page; closing the tab or quitting the browser ends it. Leave the tab open, and on a laptop, stop it from sleeping.
Why is there no sound?
Browsers block audio until you interact with the page. Pressing Set counts as that interaction, so use the button rather than reloading into a pre-set alarm. Also check the tab is not muted.
Does it work offline?
Yes, once the page has loaded. The clock reads your device's time and the tone is synthesised locally, so no network is needed.
Your data stays on your device
Everything above runs inside your browser as WebAssembly compiled from Rust. Nothing you type is uploaded, logged or stored on a server. There is no server. You can load this page once, go offline, and it still works.