# How an alarm app rings through Silent Mode

A local notification is not an alarm. Ringing through Silent Mode and Focus takes an owned audio session, a layered fallback, and an honest "scheduling was interrupted" warning.

By: Necati Doğrul · 2026-09-13 · https://necatidogrul.dev/en/notes/alarm-silent-mode · ios, audio

Everyone who starts an alarm app does the same first thing: schedule a timed notification with `UNUserNotificationCenter`. It works in the simulator, it works on the phone, it ships. Then a user writes: "It didn't ring on silent."

Because a notification is not an alarm. Its sound is at the system's mercy: Silent Mode cuts it, Focus delays or hides it, and it stops after 30 seconds anyway. Here is the structure that worked in Wakora:

## 1. Take the audio session and keep it

At alarm time the app opens an `AVAudioSession` and plays the alarm sound itself. That sound is not bound to the silent switch. The session stays open until the task is done. Background audio is declared in `Info.plist`, and you are genuinely playing audio; the "keep alive with a blank file" trick neither works nor passes review.

## 2. Keep notifications as the fallback, not the main path

If the app is swiped away, the audio session goes with it. So the notification chain is still scheduled: one at the alarm time, a backup a few minutes later. Worst case the user gets a silent-but-vibrating notification, which beats not waking at all.

## 3. Say when scheduling was interrupted

If scheduling was cut off for any reason, tell the user. Wakora shows a "alarm scheduling was interrupted, re-enable" warning on the home screen. An alarm app that fails silently collects one-star reviews.

## 4. Keep going after dismissal

Dismissing the alarm is not being awake. Two minutes later a "still up?" prompt catches going back to bed. That small screen became the most talked-about feature.

## Measurement

After these four changes the "didn't ring on silent" review stopped appearing. Explaining the mechanism in one sentence during onboarding took day-one return from 16 to 30 points. Trust in an alarm app is not built by the loudest sound but by how many times it did not stay silent.

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Necati Doğrul · https://necatidogrul.dev