Push Notifications

Implement, review, and debug local and remote notifications on iOS/macOS using UserNotifications and APNs. Covers permission flow, token registration, payload structure, foreground handling, notification actions, grouping, and rich notifications. Targets iOS 26+ with Swift 6.3, backward-compatible to iOS 16 unless noted.

Contents

• Permission Flow
• APNs Registration
• Local Notifications
• Remote Notification Payload
• Notification Handling
• Notification Actions and Categories
• Notification Grouping
• Common Mistakes
• Review Checklist
• References

Permission Flow

Request notification authorization before doing anything else. The system prompt appears only once; subsequent calls return the stored decision.

import UserNotifications

@MainActor
func requestNotificationPermission() async -> Bool {
    let center = UNUserNotificationCenter.current()
    do {
        let granted = try await center.requestAuthorization(
            options: [.alert, .sound, .badge]
        )
        return granted
    } catch {
        print("Authorization request failed: \(error)")
        return false
    }
}

Checking Current Status

Always check status before assuming permissions. The user can change settings at any time.

@MainActor
func checkNotificationStatus() async -> UNAuthorizationStatus {
    let settings = await UNUserNotificationCenter.current().notificationSettings()
    return settings.authorizationStatus
    // .notDetermined, .denied, .authorized, .provisional, .ephemeral
}

Provisional Notifications

Provisional notifications deliver quietly to the notification center without interrupting the user. The user can then choose to keep or turn them off. Use for onboarding flows where you want to demonstrate value before asking for full permission.

// Delivers silently -- no permission prompt shown to the user
try await center.requestAuthorization(options: [.alert, .sound, .badge, .provisional])

Critical Alerts

Critical alerts bypass Do Not Disturb and the mute switch. Requires a special entitlement from Apple (request via developer portal). Use only for health, safety, or security scenarios.

// Requires com.apple.developer.usernotifications.critical-alerts entitlement
try await center.requestAuthorization(
    options: [.alert, .sound, .badge, .criticalAlert]
)

Handling Denied Permissions

When the user has denied notifications, guide them to Settings with UIApplication.openSettingsURLString. Do not repeatedly prompt or nag.

APNs Registration

Use UIApplicationDelegateAdaptor to receive the device token in a SwiftUI app. The AppDelegate callbacks are the only way to receive APNs tokens.

@main
struct MyApp: App {
    @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate

    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

class AppDelegate: NSObject, UIApplicationDelegate {
    func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? = nil
    ) -> Bool {
        UNUserNotificationCenter.current().delegate = NotificationDelegate.shared
        return true
    }

    func application(
        _ application: UIApplication,
        didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data
    ) {
        let token = deviceToken.map { String(format: "%02x", $0) }.joined()
        print("APNs token: \(token)")
        // Send token to your server
        Task { await TokenService.shared.upload(token: token) }
    }

    func application(
        _ application: UIApplication,
        didFailToRegisterForRemoteNotificationsWithError error: Error
    ) {
        print("APNs registration failed: \(error.localizedDescription)")
        // Simulator always fails -- this is expected during development
    }
}

Registration Order

Request authorization first, then register for remote notifications. Registration triggers the system to contact APNs and return a device token.

@MainActor
func registerForPush() async {
    let granted = await requestNotificationPermission()
    guard granted else { return }
    UIApplication.shared.registerForRemoteNotifications()
}

Token Handling

Device tokens change. Re-send the token to your server every time didRegisterForRemoteNotificationsWithDeviceToken fires, not just the first time. The system calls this method on every app launch that calls registerForRemoteNotifications().

Local Notifications

Schedule notifications directly from the device without a server. Useful for reminders, timers, and location-based alerts.

Creating Content

let content = UNMutableNotificationContent()
content.title = "Workout Reminder"
content.subtitle = "Time to move"
content.body = "You have a scheduled workout in 15 minutes."
content.sound = .default
content.badge = 1
content.userInfo = ["workoutId": "abc123"]
content.threadIdentifier = "workouts"  // groups in notification center

Trigger Types

// Fire after a time interval (minimum 60 seconds for repeating)
let timeTrigger = UNTimeIntervalNotificationTrigger(timeInterval: 300, repeats: false)

// Fire at a specific date/time
var dateComponents = DateComponents()
dateComponents.hour = 8
dateComponents.minute = 30
let calendarTrigger = UNCalendarNotificationTrigger(
    dateMatching: dateComponents, repeats: true  // daily at 8:30 AM
)

// Fire when entering a geographic region
let region = CLCircularRegion(
    center: CLLocationCoordinate2D(latitude: 37.33