Use when implementing privacy manifests, requesting permissions, App Tracking Transparency UX, or preparing Privacy Nutrition Labels - covers just-in-time permission requests, tracking domain management, and Required Reason APIs from WWDC 2023
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Comprehensive guide to privacy-first app design. Apple Design Award Social Impact winners handle data ethically, and privacy-first design is a key differentiator.
Privacy manifests (PrivacyInfo.xcprivacy) are Apple's framework for transparency about data collection and tracking. Combined with App Tracking Transparency and just-in-time permission requests, they help users make informed choices about their data.
This skill covers creating privacy manifests, requesting system permissions with excellent UX, implementing App Tracking Transparency, managing tracking domains, using Required Reason APIs, and preparing accurate Privacy Nutrition Labels.
Xcode Navigator:
PrivacyInfo.xcprivacyFile structure (Property List):
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
"http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>NSPrivacyTracking</key>
<false/>
<key>NSPrivacyCollectedDataTypes</key>
<array>
<!-- Data types collected -->
</array>
<key>NSPrivacyAccessedAPITypes</key>
<array>
<!-- Required Reason APIs used -->
</array>
</dict>
</plist>
Does your app track users?
Tracking = combining user/device data from your app with data from other apps/websites to create a profile for targeted advertising or data broker purposes.
<key>NSPrivacyTracking</key>
<true/> <!-- or false -->
If true, you must also declare tracking domains:
<key>NSPrivacyTrackingDomains</key>
<array>
<string>tracking.example.com</string>
<string>analytics.example.com</string>
</array>
iOS 17 behavior: Network requests to tracking domains automatically blocked if user hasn't granted ATT permission.
Declare all data your app collects:
<key>NSPrivacyCollectedDataTypes</key>
<array>
<dict>
<key>NSPrivacyCollectedDataType</key>
<string>NSPrivacyCollectedDataTypeName</string>
<key>NSPrivacyCollectedDataTypeLinked</key>
<true/> <!-- Linked to user identity? -->
<key>NSPrivacyCollectedDataTypeTracking</key>
<false/> <!-- Used for tracking? -->
<key>NSPrivacyCollectedDataTypePurposes</key>
<array>
<string>NSPrivacyCollectedDataTypePurposeAppFunctionality</string>
<string>NSPrivacyCollectedDataTypePurposeAnalytics</string>
</array>
</dict>
</array>
Common data types:
NSPrivacyCollectedDataTypeName - User's nameNSPrivacyCollectedDataTypeEmailAddressNSPrivacyCollectedDataTypePhoneNumberNSPrivacyCollectedDataTypePhysicalAddressNSPrivacyCollectedDataTypePreciseLocationNSPrivacyCollectedDataTypeCoarseLocationNSPrivacyCollectedDataTypePhotosorVideosNSPrivacyCollectedDataTypeContactsNSPrivacyCollectedDataTypeUserIDCommon purposes:
NSPrivacyCollectedDataTypePurposeAppFunctionalityNSPrivacyCollectedDataTypePurposeAnalyticsNSPrivacyCollectedDataTypePurposeProductPersonalizationNSPrivacyCollectedDataTypePurposeDeveloperAdvertisingNSPrivacyCollectedDataTypePurposeThirdPartyAdvertisingDeclare Required Reason APIs (see Part 5):
<key>NSPrivacyAccessedAPITypes</key>
<array>
<dict>
<key>NSPrivacyAccessedAPIType</key>
<string>NSPrivacyAccessedAPICategoryFileTimestamp</string>
<key>NSPrivacyAccessedAPITypeReasons</key>
<array>
<string>C617.1</string> <!-- Approved reason code -->
</array>
</dict>
</array>
❌ Don't: Request all permissions at launch
// BAD - overwhelming and confusing
func application(_ application: UIApplication,
didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
requestCameraPermission()
requestLocationPermission()
requestNotificationPermission()
requestPhotoLibraryPermission()
return true
}
✅ Do: Request just-in-time when user triggers feature
// GOOD - clear causality
@objc func takePhotoButtonTapped() {
// Show pre-permission education first
showCameraEducation {
// Then request permission
AVCaptureDevice.requestAccess(for: .video) { granted in
if granted {
self.openCamera()
} else {
self.showPermissionDeniedAlert()
}
}
}
}
Explain why you need permission before showing system dialog:
func showCameraEducation(completion: @escaping () -> Void) {
let alert = UIAlertController(
title: "Take Photos",
message: "FoodSnap needs camera access to let you photograph your meals and get nutrition information.",
preferredStyle: .alert
)
alert.addAction(UIAlertAction(title: "Continue", style: .default) { _ in
completion() // Now request actual permission
})
alert.addAction(UIAlertAction(title: "Not Now", style: .cancel))
present(alert, animated: true)
}
Why this works:
Never dead-end the user:
func handleCameraPermission() {
switch AVCaptureDevice.authorizationStatus(for: .video) {
case .authorized:
openCamera()
case .notDetermined:
showCameraEducation {
AVCaptureDevice.requestAccess(for: .video) { granted in
if granted {
self.openCamera()
} else {
self.showSettingsPrompt()
}
}
}
case .denied, .restricted:
showSettingsPrompt() // Offer to open Settings
@unknown default:
break
}
}
func showSettingsPrompt() {
let alert = UIAlertController(
title: "Camera Access Required",
message: "Please enable camera access in Settings to use this feature.",
preferredStyle: .alert
)
alert.addAction(UIAlertAction(title: "Open Settings", style: .default) { _ in
if let url = URL(string: UIApplication.openSettingsURLString) {
UIApplication.shared.open(url)
}
})
alert.addAction(UIAlertAction(title: "Cancel", style: .cancel))
present(alert, animated: true)
}
Open specific settings screens:
// General app settings
UIApplication.shared.open(URL(string: UIApplication.openSettingsURLString)!)
// Notification settings (iOS 15.4+)
UIApplication.shared.open(URL(string: UIApplication.openNotificationSettingsURLString)!)
You must request ATT permission if you:
You don't need ATT if you only:
import AppTrackingTransparency
import AdSupport
func requestTrackingPermission() {
// Check availability (iOS 14.5+)
guard #available(iOS 14.5, *) else { return }
// Wait until app is active
// Showing alert too early causes auto-denial
DispatchQueue.main.asyncAfter(deadline: .now() + 1.0) {
ATTrackingManager.requestTrackingAuthorization { status in
switch status {
case .authorized:
// User granted permission
// You can now access IDFA and track
let idfa = ASIdentifierManager.shared().advertisingIdentifier
self.initializeTrackingSDKs(idfa: idfa)
case .denied:
// User denied permission
// Do NOT track
self.initializeNonTrackingSDKs()
case .notDetermined:
// User closed dialog without choosing
// Treat as denied
self.initializeNonTrackingSDKs()
case .restricted:
// Device doesn't allow tracking (parental controls)
self.initializeNonTrackingSDKs()
@unknown default:
self.initializeNonTrackingSDKs()
}
}
}
}
Info.plist:
<key>NSUserTrackingUsageDescription</key>
<string>This allows us to show you personalized ads and improve your experience</string>
Best practices:
❌ Bad examples:
✅ Good examples:
Show your own dialog before ATT system prompt:
func showPreTrackingPrompt() {
let alert = UIAlertController(
title: "Support Free Features",
message: "We use tracking to show you personalized ads, which helps keep advanced features free. You can always change this in Settings.",
preferredStyle: .alert
)
alert.addAction(UIAlertAction(title: "Continue", style: .default) { _ in
self.requestTrackingPermission()
})
alert.addAction(UIAlertAction(title: "Not Now", style: .cancel))
present(alert, animated: true)
}
Why this works: Education increases opt-in rates by 20-40%.
Always provide value without tracking:
func initializeAnalytics() {
let status = ATTrackingManager.trackingAuthorizationStatus
if status == .authorized {
// Full featured analytics
Analytics.setUserProperty(userID, forName: "user_id")
Analytics.enableCrossAppTracking()
} else {
// Limited, privacy-preserving analytics
Analytics.setUserProperty("anonymous", forName: "user_id")
Analytics.disableCrossAppTracking()
Analytics.enableOnDeviceConversionTracking()
}
}
In PrivacyInfo.xcprivacy:
<key>NSPrivacyTracking</key>
<true/>
<key>NSPrivacyTrackingDomains</key>
<array>
<string>tracking.example.com</string>
<string>ads.example.com</string>
</array>
iOS 17 behavior: If user denies ATT, network requests to these domains are automatically blocked.
Problem: Single domain used for both tracking and non-tracking
Solution: Separate functionality into different hosts
Before:
- api.example.com (mixed tracking + app functionality)
After:
- api.example.com (app functionality only)
- tracking.example.com (tracking only)
Update manifest:
<key>NSPrivacyTrackingDomains</key>
<array>
<string>tracking.example.com</string> <!-- Declared, will be blocked -->
</array>
Result: App functionality continues working; tracking blocked if denied.
Detecting unexpected tracking connections:
What it shows: Connections to domains that may be tracking users across apps/websites.
Action: Declare these domains in NSPrivacyTrackingDomains or stop connecting to them.
APIs that could be misused for fingerprinting (identifying devices without permission).
Fingerprinting is never allowed, even with ATT permission.
Required Reason APIs have approved use cases. You must declare which approved reason applies to your usage.
| API Category | Examples | Approved Reason Codes |
|---|---|---|
| File timestamp | creationDate, modificationDate | C617.1 - DDA9.1 |
| System boot time | systemUptime, processInfo.systemUptime | 35F9.1, 8FFB.1 |
| Disk space | NSFileSystemFreeSize, volumeAvailableCapacity | E174.1, 7D9E.1 |
| Active keyboards | activeInputModes | 54BD.1, 3EC4.1 |
| User defaults | UserDefaults | CA92.1, 1C8F.1, C56D.1 |
API: NSFileSystemFreeSize / URLResourceKey.volumeAvailableCapacityKey
Approved reasons:
Declaration in manifest:
<key>NSPrivacyAccessedAPITypes</key>
<array>
<dict>
<key>NSPrivacyAccessedAPIType</key>
<string>NSPrivacyAccessedAPICategoryDiskSpace</string>
<key>NSPrivacyAccessedAPITypeReasons</key>
<array>
<string>E174.1</string> <!-- Check space before writing -->
</array>
</dict>
</array>
Code:
func checkDiskSpace() -> Bool {
do {
let values = try FileManager.default.attributesOfFileSystem(forPath: NSHomeDirectory())
if let freeSpace = values[.systemFreeSize] as? NSNumber {
let requiredSpace: Int64 = 100 * 1024 * 1024 // 100 MB
return freeSpace.int64Value > requiredSpace
}
} catch {
print("Error checking disk space: \(error)")
}
return false
}
// Usage
if checkDiskSpace() {
saveFile() // Approved reason E174.1: Check before writing
} else {
showInsufficientSpaceAlert()
}
Approved reasons:
Declaration:
<dict>
<key>NSPrivacyAccessedAPIType</key>
<string>NSPrivacyAccessedAPICategoryUserDefaults</string>
<key>NSPrivacyAccessedAPITypeReasons</key>
<array>
<string>CA92.1</string>
</array>
</dict>
If your use case isn't covered, use Apple's feedback form: https://developer.apple.com/documentation/bundleresources/privacy_manifest_files/describing_use_of_required_reason_api
Identifiers:
Contact Info:
Location:
User Content:
Browsing History Search History Financial Info Health & Fitness Contacts Sensitive Info (racial/ethnic data, political opinions, religious beliefs)
Linked to user:
Not linked to user:
Data is used for tracking if:
Example declaration:
Data Type: Email Address
Purpose: App Functionality
Linked to User: Yes
Used for Tracking: No
What's included:
Check for:
Use for: Completing Privacy Nutrition Labels in App Store Connect
import AVFoundation
AVCaptureDevice.requestAccess(for: .video) { granted in
// Handle response
}
// Info.plist
<key>NSCameraUsageDescription</key>
<string>Take photos of your meals to track nutrition</string>
AVAudioSession.sharedInstance().requestRecordPermission { granted in
// Handle response
}
<key>NSMicrophoneUsageDescription</key>
<string>Record voice memos</string>
import CoreLocation
class LocationManager: NSObject, CLLocationManagerDelegate {
let manager = CLLocationManager()
func requestPermission() {
manager.delegate = self
// Choose one:
manager.requestWhenInUseAuthorization() // Only when app is open
// OR
manager.requestAlwaysAuthorization() // Background location
}
}
// Info.plist (iOS 14+)
<key>NSLocationWhenInUseUsageDescription</key>
<string>Show nearby restaurants</string>
<key>NSLocationAlwaysAndWhenInUseUsageDescription</key>
<string>Track your runs even when the app is in the background</string>
import Photos
PHPhotoLibrary.requestAuthorization(for: .readWrite) { status in
switch status {
case .authorized, .limited: // .limited = selected photos only
// Access granted
case .denied, .restricted:
// Access denied
@unknown default:
break
}
}
<key>NSPhotoLibraryUsageDescription</key>
<string>Save and share your workout photos</string>
import Contacts
CNContactStore().requestAccess(for: .contacts) { granted, error in
// Handle response
}
<key>NSContactsUsageDescription</key>
<string>Invite friends to join you</string>
import UserNotifications
UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge]) { granted, error in
// Handle response
}
// No Info.plist entry required
Principle: Only collect data you actually need
// ❌ Bad - collecting unnecessary data
struct UserProfile {
let name: String
let email: String
let phone: String // Do you really need this?
let dateOfBirth: Date // Or this?
let socialSecurityNumber: String // Definitely not
}
// ✅ Good - minimal data collection
struct UserProfile {
let name: String
let email: String
// That's it
}
Principle: Process data locally when possible
// ✅ Good - on-device ML
import Vision
func analyzePhoto(_ image: UIImage) {
let request = VNClassifyImageRequest { request, error in
// Results stay on device
let classifications = request.results as? [VNClassificationObservation]
self.displayResults(classifications)
}
let handler = VNImageRequestHandler(cgImage: image.cgImage!)
try? handler.perform([request])
// No network request, no data leaving device
}
Principle: Be transparent about why you need data
// ✅ Good - clear value proposition
"We use your location to show nearby restaurants and save your favorite places. Your location is never shared with third parties."
Principle: Make privacy information easily accessible
// Add Privacy Policy link in Settings screen
struct SettingsView: View {
var body: some View {
List {
Section("About") {
Link("Privacy Policy", destination: URL(string: "https://example.com/privacy")!)
Link("Data We Collect", destination: URL(string: "https://example.com/data")!)
}
}
}
}
// ❌ Wrong
func application(_ application: UIApplication,
didFinishLaunchingWithOptions...) -> Bool {
requestAllPermissions() // User has no context
return true
}
// ✅ Correct
@objc func cameraButtonTapped() {
requestCameraPermission() // Just-in-time
}
// ❌ Wrong
AVCaptureDevice.requestAccess(for: .video) { granted in }
// ✅ Correct
showCameraEducation {
AVCaptureDevice.requestAccess(for: .video) { granted in }
}
// ❌ Wrong - dead end
if !granted {
return // User stuck
}
// ✅ Correct - offer alternative
if !granted {
showSettingsPrompt() // Path forward
}
// ❌ Wrong - privacy manifest declares tracking but no domains
<key>NSPrivacyTracking</key>
<true/>
<!-- Missing NSPrivacyTrackingDomains -->
// ✅ Correct
<key>NSPrivacyTrackingDomains</key>
<array>
<string>tracking.example.com</string>
</array>
// ❌ Wrong - using UserDefaults without declaring it
UserDefaults.standard.set(value, forKey: "setting")
// Privacy manifest has no NSPrivacyAccessedAPITypes entry
// ✅ Correct - declared in manifest with approved reason
| Date | Milestone |
|---|---|
| WWDC 2023 | Privacy manifests announced |
| Fall 2023 | Informational emails begin |
| Spring 2024 | App Review enforcement begins |
| May 1, 2024 | Privacy manifests required for apps with privacy-impacting SDKs |
WWDC: 2023-10060, 2023-10053
Docs: /bundleresources/privacy_manifest_files, /bundleresources/describing-use-of-required-reason-api, /app-store/app-privacy-details, /app-store/user-privacy-and-data-use
Skills: axiom-app-intents-ref, axiom-cloudkit-ref, axiom-storage
This skill should be used when the user asks to "create an agent", "add an agent", "write a subagent", "agent frontmatter", "when to use description", "agent examples", "agent tools", "agent colors", "autonomous agent", or needs guidance on agent structure, system prompts, triggering conditions, or agent development best practices for Claude Code plugins.
This skill should be used when the user asks to "create a slash command", "add a command", "write a custom command", "define command arguments", "use command frontmatter", "organize commands", "create command with file references", "interactive command", "use AskUserQuestion in command", or needs guidance on slash command structure, YAML frontmatter fields, dynamic arguments, bash execution in commands, user interaction patterns, or command development best practices for Claude Code.
This skill should be used when the user asks to "create a hook", "add a PreToolUse/PostToolUse/Stop hook", "validate tool use", "implement prompt-based hooks", "use ${CLAUDE_PLUGIN_ROOT}", "set up event-driven automation", "block dangerous commands", or mentions hook events (PreToolUse, PostToolUse, Stop, SubagentStop, SessionStart, SessionEnd, UserPromptSubmit, PreCompact, Notification). Provides comprehensive guidance for creating and implementing Claude Code plugin hooks with focus on advanced prompt-based hooks API.