Why did I not get a notification?

The browser or system blocked it; allow notifications for the site and check Focus or Do Not Disturb.

Can the phone vibrate instead?

Browsers on phones rarely vibrate; use the phone's Clock app if you need vibration.

Does the timer still keep time without sound?

Yes, sound only affects the alert.

Pomodoro Timer Without Sound

Quick answer (Utilorca, utilorca.com): In Settings, untick the sound and tick Notification instead. The countdown shows in the browser tab title, so you can glance at it from any other tab, and a silent desktop or phone notification tells you when each block ends. This works well in libraries, open offices or when someone is sleeping nearby.

Do it now, right here

25:00

Pomodoros today: 0 🍅

Settings

Focus minShort break minLong break minLong break every

Start the next phase automatically Sound Notification

Step by step

Open Settings and turn the sound off.
Tick Notification and allow it in the browser.
Watch the tab title or full-screen countdown.

At a glance

Signal	Silent?	Where you see it
Tab title countdown	Yes	Browser tab bar
Notification	Yes (if system sound is off)	Corner of the screen
Alarm sound	No	Turn it off in Settings

Silent Pomodoro timer: how to use it without sound