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axiom-push-notifications-ref

axiom-push-notifications-ref

github.com/charleswiltgenDevelopment1.2k65 installsUpdated today
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About axiom-push-notifications-ref

An API reference skill for developers implementing Apple push notifications. It brings together APNs transport, UserNotifications APIs, payload formats, Live Activities, and local notification references.

Key features

  1. 01APNs endpoints, headers, and responses
  2. 02JWT authentication reference
  3. 03Payload keys and examples
  4. 04UserNotifications API reference
  5. 05Live Activity push fields
  6. 06Local notification triggers

Use cases

  1. 01Building APNs requests
  2. 02Implementing notification authorization and actions
  3. 03Preparing Live Activity payloads
  4. 04Scheduling local notifications

Install

Copy the command and run it in a terminal.

$npx skills add https://github.com/charleswiltgen/axiom --skill axiom-push-notifications-ref

After installing, type/axiom-push-notifications-refin Claude Code to confirm it loaded.

Details

From the project README

Push Notifications API Reference

Comprehensive API reference for APNs HTTP/2 transport, UserNotifications framework, and push-driven features including Live Activities and broadcast push.

Quick Reference

// AppDelegate — minimal remote notification setup
class AppDelegate: NSObject, UIApplicationDelegate, UNUserNotificationCenterDelegate {
    func application(_ application: UIApplication,
                     didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        UNUserNotificationCenter.current().delegate = self
        return true
    }

    func application(_ application: UIApplication,
                     didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
        let token = deviceToken.map { String(format: "%02x", $0) }.joined()
        sendTokenToServer(token)
    }

    func application(_ application: UIApplication,
                     didFailToRegisterForRemoteNotificationsWithError error: Error) {
        print("Registration failed: \(error)")
    }

    // Show notifications when app is in foreground
    func userNotificationCenter(_ center: UNUserNotificationCenter,
                                willPresent notification: UNNotification) async -> UNNotificationPresentationOptions {
        return [.banner, .sound, .badge]
    }

    // Handle notification tap / action response
    func userNotificationCenter(_ center: UNUserNotificationCenter,
                                didReceive response: UNNotificationResponse) async {
        let userInfo = response.notification.request.content.userInfo
        // Route to appropriate screen based on userInfo
    }
}

APNs Transport Reference

Endpoints
EnvironmentHostPort
Developmentapi.sandbox.push.apple.com443 or 2197
Productionapi.push.apple.com443 or 2197
Request Format
POST /3/device/{device_token}
Host: api.push.apple.com
Authorization: bearer {jwt_token}
apns-topic: {bundle_id}
apns-push-type: alert
Content-Type: application/json
APNs Headers
HeaderRequiredValuesNotes
apns-push-typeYesalert, background, liveactivity, voip, complication, fileprovider, mdm, locationMust match payload content
apns-topicYesBundle ID (or .push-type.liveactivity suffix)Required for token-based auth
apns-priorityNo10 (immediate), 5 (power-conscious), 1 (low)Default: 10 for alert, 5 for background
apns-expirationNoUNIX timestamp or 00 = deliver once, don't store
apns-collapse-idNoString ≤64 bytesReplaces matching notification on device
apns-idNoUUID (lowercase)Returned by APNs for tracking
authorizationToken authbearer {JWT}Not needed for certificate auth
apns-unique-idResponse onlyUUIDUse with Push Notifications Console delivery log
Response Codes
StatusMeaningCommon Cause
200Success
400Bad requestMalformed JSON, missing required header
403ForbiddenExpired JWT, wrong team/key, topic mismatch
404Not foundInvalid device token path
405Method not allowedNot using POST
410UnregisteredDevice token no longer active (app uninstalled)
413Payload too largeExceeds 4KB (5KB for VoIP)
429Too many requestsRate limited by APNs
500Internal server errorAPNs issue, retry
503Service unavailableAPNs overloaded, retry with backoff

JWT Authentication Reference

JWT Header
{ "alg": "ES256", "kid": "{10-char Key ID}" }
JWT Claims
{ "iss": "{10-char Team ID}", "iat": {unix_timestamp} }
Rules
RuleDetail
AlgorithmES256 (P-256 curve)
Signing keyAPNs auth key (.p8 from developer portal)
Token lifetimeMax 1 hour (403 ExpiredProviderToken if older)
Refresh intervalBetween 20 and 60 minutes
ScopeOne key works for all apps in team, both environments
Authorization Header Format
authorization: bearer eyAia2lkIjog...

Payload Reference

aps Dictionary Keys
KeyTypePurposeSince
alertDict/StringAlert contentiOS 10
badgeNumberApp icon badge (0 removes)iOS 10
soundString/DictAudio playbackiOS 10
thread-idStringNotification groupingiOS 10
categoryStringActionable notification typeiOS 10
content-availableNumber (1)Silent background pushiOS 10
mutable-contentNumber (1)Triggers service extensioniOS 10
target-content-idStringWindow/content identifieriOS 13
interruption-levelStringpassive/active/time-sensitive/criticaliOS 15
relevance-scoreNumber 0-1Notification summary sortingiOS 15
filter-criteriaStringFocus filter matchingiOS 15
stale-dateNumberUNIX timestamp (Live Activity)iOS 16.1
content-stateDictLive Activity content updateiOS 16.1
timestampNumberUNIX timestamp (Live Activity)iOS 16.1
eventStringstart/update/end (Live Activity)iOS 16.1
dismissal-dateNumberUNIX timestamp (Live Activity)iOS 16.1
attributes-typeStringLive Activity struct nameiOS 17
attributesDictLive Activity init dataiOS 17
Alert Dictionary Keys
KeyTypePurpose
titleStringShort title
subtitleStringSecondary description
bodyStringFull message
launch-imageStringLaunch screen filename
title-loc-keyStringLocalization key for title
title-loc-args[String]Title format arguments
subtitle-loc-keyStringLocalization key for subtitle
subtitle-loc-args[String]Subtitle format arguments
loc-keyStringLocalization key for body
loc-args[String]Body format arguments
Sound Dictionary (Critical Alerts)
{ "critical": 1, "name": "alarm.aiff", "volume": 0.8 }
Interruption Level Values
ValueBehaviorRequires
passiveNo sound/wake. Notification summary only.Nothing
activeDefault. Sound + banner.Nothing
time-sensitiveBreaks scheduled delivery. Banner persists.Time Sensitive capability
criticalOverrides DND and ringer switch.Apple approval + entitlement
Example Payloads
Basic Alert
{
    "aps": {
        "alert": {
            "title": "New Message",
            "subtitle": "From Alice",
            "body": "Hey, are you free for lunch?"
        },
        "badge": 3,
        "sound": "default"
    }
}
Localized with loc-key/loc-args
{
    "aps": {
        "alert": {
            "title-loc-key": "MESSAGE_TITLE",
            "title-loc-args": ["Alice"],
            "loc-key": "MESSAGE_BODY",
            "loc-args": ["Alice", "lunch"]
        },
        "sound": "default"
    }
}
Silent Background Push
{
    "aps": {
        "content-available": 1
    },
    "custom-key": "sync-update"
}
Rich Notification (Service Extension)
{
    "aps": {
        "alert": {
            "title": "Photo shared",
            "body": "Alice shared a photo with you"
        },
        "mutable-content": 1,
        "sound": "default"
    },
    "image-url": "https://example.com/photo.jpg"
}
Critical Alert
{
    "aps": {
        "alert": {
            "title": "Server Down",
            "body": "Production database is unreachable"
        },
        "sound": { "critical": 1, "name": "default", "volume": 1.0 },
        "interruption-level": "critical"
    }
}
Time-Sensitive with Category
{
    "aps": {
        "alert": {
            "title": "Package Delivered",
            "body": "Your order has been delivered to the front door"
        },
        "interruption-level": "time-sensitive",
        "category": "DELIVERY",
        "sound": "default"
    },
    "order-id": "12345"
}

UNUserNotificationCenter API Reference

Key Methods
MethodPurpose
requestAuthorization(options:)Request permission
notificationSettings()Check current status
add(_:)Schedule notification request
getPendingNotificationRequests()List scheduled
removePendingNotificationRequests(withIdentifiers:)Cancel scheduled
getDeliveredNotifications()List in notification center
removeDeliveredNotifications(withIdentifiers:)Remove from center
setNotificationCategories(_:)Register actionable types
setBadgeCount(_:)Update badge (iOS 16+)
supportsContentExtensionsCheck content extension support
UNAuthorizationOptions
OptionPurpose
.alertDisplay alerts
.badgeUpdate badge count
.soundPlay sounds
.carPlayShow in CarPlay
.criticalAlertCritical alerts (requires entitlement)
.provisionalTrial delivery without prompting
.providesAppNotificationSettings"Configure in App" button in Settings
.announcementSiri announcement (deprecated iOS 15+)
UNAuthorizationStatus
ValueMeaning
.notDeterminedNo prompt shown yet
.deniedUser denied or disabled in Settings
.authorizedUser explicitly granted
.provisionalProvisional trial delivery
.ephemeralApp Clip temporary
Request Authorization
let center = UNUserNotificationCenter.current()

let granted = try await center.requestAuthorization(options: [.alert, .sound, .badge])
if granted {
    await MainActor.run {
        UIApplication.shared.registerForRemoteNotifications()
    }
}
Check Settings
let settings = await center.notificationSettings()

switch settings.authorizationStatus {
case .authorized: break
case .denied:
    // Direct user to Settings
case .provisional:
    // Upgrade to full authorization
case .notDetermined:
    // Request authorization
case .ephemeral:
    // App Clip — temporary
@unknown default: break
}
Delegate Methods
// Foreground presentation — called when notification arrives while app is active
func userNotificationCenter(_ center: UNUserNotificationCenter,
                            willPresent notification: UNNotification) async
    -> UNNotificationPresentationOptions {
    return [.banner, .sound, .badge]
}

// Action response — called when user taps notification or action button
func userNotificationCenter(_ center: UNUserNotificationCenter,
                            didReceive response: UNNotificationResponse) async {
    let actionIdentifier = response.actionIdentifier
    let userInfo = response.notification.request.content.userInfo

    switch actionIdentifier {
    case UNNotificationDefaultActionIdentifier:
        // User tapped notification body
        break
    case UNNotificationDismissActionIdentifier:
        // User dismissed (requires .customDismissAction on category)
        break
    default:
        // Custom action
        break
    }
}

// Settings — called when user taps "Configure in App" from notification settings
func userNotificationCenter(_ center: UNUserNotificationCenter,
                            openSettingsFor notification: UNNotification?) {
    // Navigate to in-app notification settings
}

UNNotificationCategory and UNNotificationAction API

Category Registration
let likeAction = UNNotificationAction(
    identifier: "LIKE",
    title: "Like",
    options: []
)

let replyAction = UNTextInputNotificationAction(
    identifier: "REPLY",
    title: "Reply",
    options: [],
    textInputButtonTitle: "Send",
    textInputPlaceholder: "Type a message..."
)

let deleteAction = UNNotificationAction(
    identifier: "DELETE",
    title: "Delete",
    options: [.destructive, .authenticationRequired]
)

let messageCategory = UNNotificationCategory(
    identifier: "MESSAGE",
    actions: [likeAction, replyAction, deleteAction],
    intentIdentifiers: [],
    hiddenPreviewsBodyPlaceholder: "New message",
    categorySummaryFormat: "%u more messages",
    options: [.customDismissAction]
)

UNUserNotificationCenter.current().setNotificationCategories([messageCategory])
Action Options
OptionEffect
.authenticationRequiredRequires device unlock
.destructiveRed text display
.foregroundLaunches app to foreground
Category Options
OptionEffect
.customDismissActionFires delegate on dismiss
.allowInCarPlayShow actions in CarPlay
.hiddenPreviewsShowTitleShow title when previews hidden
.hiddenPreviewsShowSubtitleShow subtitle when previews hidden
.allowAnnouncementSiri can announce (deprecated iOS 15+)
UNNotificationActionIcon (iOS 15+)
let icon = UNNotificationActionIcon(systemImageName: "hand.thumbsup")
let action = UNNotificationAction(
    identifier: "LIKE",
    title: "Like",
    options: [],
    icon: icon
)

UNNotificationServiceExtension API

Modifies notification content before display. Runs in a separate extension process.

Lifecycle
MethodWindowPurpose
didReceive(_:withContentHandler:)~30 secondsModify notification content
serviceExtensionTimeWillExpire()Called at deadlineDeliver best attempt immediately
Implementation
class NotificationService: UNNotificationServiceExtension {
    var contentHandler: ((UNNotificationContent) -> Void)?
    var bestAttemptContent: UNMutableNotificationContent?

    override func didReceive(_ request: UNNotificationRequest,
                             withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
        self.contentHandler = contentHandler
        bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)

        guard let content = bestAttemptContent,
              let imageURLString = content.userInfo["image-url"] as? String,
              let imageURL = URL(string: imageURLString) else {
            contentHandler(request.content)
            return
        }

        // Download and attach image
        let task = URLSession.shared.downloadTask(with: imageURL) { url, _, error in
            defer { contentHandler(content) }
            guard let url = url, error == nil else { return }

            let attachment = try? UNNotificationAttachment(
                identifier: "image",
                url: url,
                options: [UNNotificationAttachmentOptionsTypeHintKey: "public.jpeg"]
            )
            if let attachment = attachment {
                content.attachments = [attachment]
            }
        }
        task.resume()
    }

    override func serviceExtensionTimeWillExpire() {
        if let content = bestAttemptContent {
            contentHandler?(content)
        }
    }
}
Supported Attachment Types
TypeExtensionsMax Size
Image.jpg, .gif, .png10 MB
Audio.aif, .wav, .mp35 MB
Video.mp4, .mpeg50 MB
Payload Requirement

The notification payload must include "mutable-content": 1 in the aps dictionary for the service extension to fire.


Local Notifications API

Trigger Types
TriggerUse CaseRepeating
UNTimeIntervalNotificationTriggerAfter N secondsYes (≥60s)
UNCalendarNotificationTriggerSpecific date/timeYes
UNLocationNotificationTriggerEnter/exit regionYes
Time Interval Trigger
let content = UNMutableNotificationContent()
content.title = "Reminder"
content.body = "Time to take a break"
content.sound = .default

let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 300, repeats: false)

let request = UNNotificationRequest(
    identifier: "break-reminder",
    content: content,
    trigger: trigger
)

try await UNUserNotificationCenter.current().add(request)
Calendar Trigger
var dateComponents = DateComponents()
dateComponents.hour = 9
dateComponents.minute = 0

let trigger = UNCalendarNotificationTrigger(dateMatching: dateComponents, repeats: true)

let request = UNNotificationRequest(
    identifier: "daily-9am",
    content: content,
    trigger: trigger
)

try await UNUserNotificationCenter.current().add(request)
Location Trigger
import CoreLocation

let center = CLLocationCoordinate2D(latitude: 37.3349, longitude: -122.0090)
let region = CLCircularRegion(center: center, radius: 100, identifier: "apple-park")
region.notifyOnEntry = true
region.notifyOnExit = false

let trigger = UNLocationNotificationTrigger(region: region, repeats: false)

let request = UNNotificationRequest(
    identifier: "arrived-at-office",
    content: content,
    trigger: trigger
)

try await UNUserNotificationCenter.current().add(request)
Limitations
LimitationDetail
Minimum repeat interval60 seconds for UNTimeIntervalNotificationTrigger
Location authorizationLocation trigger requires When In Use or Always authorization
No service extensionsLocal notifications do not trigger UNNotificationServiceExtension
No background wakeLocal notifications cannot use content-available for background processing
App extensionsLocal notifications cannot be scheduled from app extensions (use app group + main app)
Pending limit64 pending notification requests per app

Live Activity Push Headers

Required Headers
HeaderValue
apns-push-typeliveactivity
apns-topic{bundleID}.push-type.liveactivity
apns-priority5 (routine) or 10 (time-sensitive)
Event Types
EventPurposeRequired Fields
startStart Live Activity remotelyattributes-type, attributes, content-state, timestamp
updateUpdate contentcontent-state, timestamp
endEnd Live Activitytimestamp (content-state optional)
Update Payload
{
    "aps": {
        "timestamp": 1709913600,
        "event": "update",
        "content-state": {
            "homeScore": 2,
            "awayScore": 1,
            "inning": "Top 7"
        }
    }
}
Start Payload (Push-to-Start Token)
{
    "aps": {
        "timestamp": 1709913600,
        "event": "start",
        "content-state": {
            "homeScore": 0,
            "awayScore": 0,
            "inning": "Top 1"
        },
        "attributes-type": "GameAttributes",
        "attributes": {
            "homeTeam": "Giants",
            "awayTeam": "Dodgers"
        },
        "alert": {
            "title": "Game Starting",
            "body": "Giants vs Dodgers is about to begin"
        }
    }
}
Start Payload (Channel-Based)
{
    "aps": {
        "timestamp": 1709913600,
        "event": "start",
        "content-state": {
            "homeScore": 0,
            "awayScore": 0,
            "inning": "Top 1"
        },
        "attributes-type": "GameAttributes",
        "attributes": {
            "homeTeam": "Giants",
            "awayTeam": "Dodgers"
        }
    }
}
End Payload
{
    "aps": {
        "timestamp": 1709913600,
        "event": "end",
        "dismissal-date": 1709917200,
        "content-state": {
            "homeScore": 5,
            "awayScore": 3,
            "inning": "Final"
        }
    }
}
Push-to-Start Token
// Observe push-to-start tokens (iOS 17.2+)
for await token in Activity<GameAttributes>.pushToStartTokenUpdates {
    let tokenString = token.map { String(format: "%02x", $0) }.joined()
    sendPushToStartTokenToServer(tokenString)
}
Activity Push Token
// Observe activity-specific push tokens
for await tokenData in activity.pushTokenUpdates {
    let token = tokenData.map { String(format: "%02x", $0) }.joined()
    sendActivityTokenToServer(token, activityId: activity.id)
}

Content-state encoding rule: the system always uses default JSONDecoder — do not use custom encoding strategies in your ActivityAttributes.ContentState.


Broadcast Push API (iOS 18+)

Server-to-many push for Live Activities without tracking individual device tokens.

Endpoint
POST /4/broadcasts/apps/{TOPIC}
Headers
HeaderValue
apns-push-typeliveactivity
apns-channel-id{channelID}
authorizationbearer {JWT}
Subscribe via Channel
try Activity.request(
    attributes: attributes,
    content: .init(state: initialState, staleDate: nil),
    pushType: .channel(channelId)
)
Channel Storage Policies
PolicyBehaviorBudget
No StorageDeliver only to connected devicesHigher
Most Recent MessageStore latest for offline devicesLower

Command-Line Testing

JWT Generation
JWT_ISSUE_TIME=$(date +%s)
JWT_HEADER=$(printf '{ "alg": "ES256", "kid": "%s" }' "${AUTH_KEY_ID}" | openssl base64 -e -A | tr -- '+/' '-_' | tr -d =)
JWT_CLAIMS=$(printf '{ "iss": "%s", "iat": %d }' "${TEAM_ID}" "${JWT_ISSUE_TIME}" | openssl base64 -e -A | tr -- '+/' '-_' | tr -d =)
JWT_HEADER_CLAIMS="${JWT_HEADER}.${JWT_CLAIMS}"
JWT_SIGNED_HEADER_CLAIMS=$(printf "${JWT_HEADER_CLAIMS}" | openssl dgst -binary -sha256 -sign "${TOKEN_KEY_FILE_NAME}" | openssl base64 -e -A | tr -- '+/' '-_' | tr -d =)
AUTHENTICATION_TOKEN="${JWT_HEADER}.${JWT_CLAIMS}.${JWT_SIGNED_HEADER_CLAIMS}"
Send Alert Push
curl -v \
  --header "apns-topic: $TOPIC" \
  --header "apns-push-type: alert" \
  --header "authorization: bearer $AUTHENTICATION_TOKEN" \
  --data '{"aps":{"alert":"test"}}' \
  --http2 https://${APNS_HOST_NAME}/3/device/${DEVICE_TOKEN}
Send Live Activity Push
curl \
  --header "apns-topic: com.example.app.push-type.liveactivity" \
  --header "apns-push-type: liveactivity" \
  --header "apns-priority: 10" \
  --header "authorization: bearer $AUTHENTICATION_TOKEN" \
  --data '{
      "aps": {
          "timestamp": '$(date +%s)',
          "event": "update",
          "content-state": { "score": "2-1" }
      }
  }' \
  --http2 https://api.sandbox.push.apple.com/3/device/$ACTIVITY_PUSH_TOKEN
Simulator Push
xcrun simctl push booted com.example.app payload.json
Simulator Payload File
{
    "Simulator Target Bundle": "com.example.app",
    "aps": {
        "alert": { "title": "Test", "body": "Hello" },
        "sound": "default"
    }
}

Resources

WWDC: 2021-10091, 2023-10025, 2023-10185, 2024-10069

Docs: /usernotifications, /usernotifications/sending-notification-requests-to-apns, /usernotifications/generating-a-remote-notification, /activitykit

Skills: axiom-push-notifications, axiom-push-notifications-diag, axiom-extensions-widgets

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