This distinction explains almost every complaint people have ever had about third-party iPhone alarms, and it is invisible from the App Store listing.

The two mechanisms

 System alarmNotification alarm
Rings in Silent modeYesDepends on the alert type
Rings through FocusYesCan be suppressed
Full-screen takeoverYesUsually a banner
Survives a restartYesHistorically unreliable
Asks a special permissionYes, to schedule alarmsOnly notification permission
Available sinceiOS 26, via AlarmKitAlways

Why so many apps were notification-based

Because there was no alternative. Until iOS 26 there was no public way for a third-party app to schedule a genuine alarm. Developers used time-sensitive notifications, or critical alerts where Apple had granted the entitlement, and built workarounds around the limitations.

This is worth stating fairly: apps that shipped notification-based alarms before iOS 26 were not cutting corners. They were doing the only thing available. The situation only changed recently.

How to tell which you have

  1. Did it ask permission to schedule alarms? AlarmKit apps must. A notification-based app only asks for notification permission. This is the quickest signal.
  2. What is the minimum iOS version? AlarmKit needs iOS 26. An app supporting iOS 15, 16 or 17 has a non-AlarmKit path for those users, though it may use both.
  3. Does it take over the screen? A system alarm presents full-screen. A banner suggests a notification.
  4. Test it. Silent mode plus a Focus plus a locked phone. This is definitive.

We do not claim which mechanism any particular competitor uses, because their listings do not say. Test the app you are relying on, ours included.

Why Mornio has no fallback

Mornio uses AlarmKit exclusively. There is no notification path, which is why it requires iOS 26.1 and cannot run on older iPhones at all.

We could have shipped a notification version for older devices and reached far more people. We chose not to, because an alarm that a Focus mode can silence is not an alarm, and shipping one under the same name would make our own reliability claims meaningless. It is a genuine trade-off with a genuine cost.

What to do if your alarm app is notification-based

It may still work fine, particularly if you do not use Focus modes overnight. But for anything that matters: