AlarmKit

Schedule prominent alarms and countdown timers that surface on the Lock Screen, Dynamic Island, StandBy, and paired Apple Watch when firing. Targets iOS 26+ / iPadOS 26+.

UI Boundary: AlarmKit alerts use system-managed alert UI that breaks through Focus and Silent modes. Custom UI is limited to countdown and paused Live Activity states rendered by a Widget Extension.

Contents

• Authorization & Setup
• Scheduling Alarms
• Countdown Timers
• Alarm State Observation
• Widget Extension Live Activity
• Common Mistakes
• Review Checklist
• References

Authorization & Setup

Add NSAlarmKitUsageDescription to Info.plist. Request authorization before scheduling alarms:

import AlarmKit

func setupAlarmKit() async throws {
    let status = await AlarmManager.shared.requestAuthorization()
    guard status == .authorized else { throw AlarmError.unauthorized }
}

Scheduling Alarms

Construct and schedule an alarm with firing date and stop actions:

let alarm = Alarm(
    id: UUID(),
    schedule: .time(Date().addingTimeInterval(3600)),
    title: "Morning Medication",
    stopAction: .dismiss,
    secondaryAction: .snooze(duration: 300)
)

try await AlarmManager.shared.schedule(alarm)

Countdown Timers

Create active countdown experiences that present live timers across Dynamic Island and Lock Screen:

let timer = Alarm(
    id: UUID(),
    schedule: .countdown(duration: 600),
    title: "Tea Steep",
    stopAction: .dismiss
)

try await AlarmManager.shared.schedule(timer)

Alarm State Observation

Observe active alarms and firing transitions asynchronously:

Task {
    for await activeAlarms in AlarmManager.shared.alarms {
        for alarm in activeAlarms {
            print("Alarm \(alarm.title): \(alarm.state)")
        }
    }
}

Widget Extension Live Activity

Render custom UI for countdown and paused states in a Widget Extension conforming to ActivityConfiguration(for: AlarmAttributes<MyMetadata>.self):

import WidgetKit
import SwiftUI
import AlarmKit

struct AlarmLiveActivity: Widget {
    var body: some WidgetConfiguration {
        ActivityConfiguration(for: AlarmAttributes<MyMetadata>.self) { context in
            // Lock Screen presentation
            Text(context.state.presentationState.title)
        } dynamicIsland: { context in
            DynamicIsland {
                DynamicIslandExpandedRegion(.leading) {
                    Image(systemName: "alarm")
                }
                DynamicIslandExpandedRegion(.trailing) {
                    Text(context.state.schedule, style: .timer)
                }
            } compactLeading: {
                Image(systemName: "alarm")
            } compactTrailing: {
                Text(context.state.schedule, style: .timer)
            } minimal: {
                Image(systemName: "alarm")
            }
        }
    }
}

Common Mistakes

• Attempting custom firing alert UI: Firing alerts are strictly system-managed. Custom views only apply to countdown Live Activities.
• Missing NSAlarmKitUsageDescription: Throws unhandled exceptions when calling requestAuthorization().
• Scheduling without authorization check: Alarms scheduled while unauthorized fail silently or throw errors.
• Ignoring state observation stream: Fails to update in-app UI when the user dismisses an alarm via the Lock Screen or Apple Watch.
• Confusing AlarmKit with UserNotifications: Use AlarmKit for critical alarms that must break through Silent/Focus; use UserNotifications for standard app alerts.

Review Checklist

• NSAlarmKitUsageDescription declared in target Info.plist
• AlarmManager.shared.requestAuthorization() confirmed authorized
• Firing schedule and stop/snooze actions configured
• Widget Extension matches AlarmAttributes generic metadata
• State changes observed via AlarmManager.shared.alarms

References

• Patterns and code: references/alarmkit-patterns.md
• AlarmKit
• AlarmManager
• AlarmAttributes
• Scheduling an alarm