Notes

Keep the window in the foreground

Cosmos lives in a browser tab. The tab doesn’t need to be the active tab, but its browser window should stay in the foreground; when the window is in the background or minimized, the reminder sound may not play. The best setup is to keep the Cosmos tab in the browser window you actually work in.

Not recommended on phones

The page opens and renders fine on mobile, but the reminder sound won’t play once the browser leaves the foreground or the screen locks. Phones can’t provide reliable reminders for now.

A reminder didn’t arrive on time?

Browsers may throttle or suspend pages, delaying reminders. When Cosmos recovers, it sends the missed reminder once and restarts the interval from that moment.

No sound at all?

Browsers restrict autoplay by default. After the page reloads, select “Re-enable reminder sound” to bring it back.

Where are my settings stored?

Your reminder interval is saved only in this browser and never uploaded; clearing site data resets it to the default.

Supported environment

Desktop Chrome on macOS is the primary target; other browsers and platforms aren’t fully verified.