Mobile App Deep Linking

Deep linking takes users directly to specific content inside your app instead of the home screen. A link like myapp://orders/123 or https://myapp.com/orders/123 opens the order detail screen, not the login page. Done well, deep links create seamless transitions between web, email, push notifications, and the app itself.

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Deep Link Types

URI Scheme (Custom):
  myapp://orders/123
  - Works only if app is installed
  - Cannot verify ownership
  - Falls back to nothing (error in browser)
  - ⚠ Deprecated for most use cases

Universal Links (iOS):
  https://myapp.com/orders/123
  - Opens app if installed, website if not
  - Verified ownership (apple-app-site-association)
  - Seamless web-to-app transition

App Links (Android):
  https://myapp.com/orders/123
  - Opens app if installed, website if not
  - Verified ownership (assetlinks.json)
  - Same URL works on both platforms

Deferred Deep Links:
  User clicks link → App not installed → App Store → Install → 
  App opens to SPECIFIC content from original link
  - Requires deep link service (Branch, Firebase Dynamic Links)

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iOS Universal Links

// apple-app-site-association (AASA)
// Hosted at: https://myapp.com/.well-known/apple-app-site-association
{
    "applinks": {
        "apps": [],
        "details": [
            {
                "appID": "TEAM_ID.com.company.myapp",
                "paths": [
                    "/orders/*",
                    "/products/*",
                    "/profile/*",
                    "NOT /api/*",
                    "NOT /static/*"
                ]
            }
        ]
    }
}

// Handle Universal Links in iOS
class SceneDelegate: UIResponder, UIWindowSceneDelegate {
    func scene(_ scene: UIScene, continue userActivity: NSUserActivity) {
        guard userActivity.activityType == NSUserActivityTypeBrowsingWeb,
              let url = userActivity.webpageURL else { return }
        
        handleDeepLink(url)
    }
    
    func handleDeepLink(_ url: URL) {
        let pathComponents = url.pathComponents
        
        switch pathComponents.first {
        case "orders":
            if let orderId = pathComponents.last {
                navigator.navigate(to: .orderDetail(id: orderId))
            }
        case "products":
            if let productId = pathComponents.last {
                navigator.navigate(to: .productDetail(id: productId))
            }
        default:
            navigator.navigate(to: .home)
        }
    }
}

---

Android App Links

// assetlinks.json
// Hosted at: https://myapp.com/.well-known/assetlinks.json
[{
    "relation": ["delegate_permission/common.handle_all_urls"],
    "target": {
        "namespace": "android_app",
        "package_name": "com.company.myapp",
        "sha256_cert_fingerprints": [
            "AB:CD:EF:12:34:56:..."
        ]
    }
}]

// Handle App Links in Android
class DeepLinkActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        
        intent?.data?.let { uri ->
            handleDeepLink(uri)
        }
    }
    
    private fun handleDeepLink(uri: Uri) {
        when {
            uri.path?.startsWith("/orders/") == true -> {
                val orderId = uri.lastPathSegment
                navigator.navigateTo(OrderDetailScreen(orderId))
            }
            uri.path?.startsWith("/products/") == true -> {
                val productId = uri.lastPathSegment
                navigator.navigateTo(ProductDetailScreen(productId))
            }
            else -> navigator.navigateTo(HomeScreen)
        }
    }
}

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Anti-Patterns

Anti-Pattern	Consequence	Fix
Only URI schemes	No fallback if app not installed	Universal Links / App Links
No deferred deep links	Post-install loses original intent	Branch, Firebase Dynamic Links
Auth wall on deep link	User logs in, loses context	Queue deep link, resume after auth
No deep link validation	Broken links in production	Automated deep link testing
Different URLs per platform	Fragmented link management	Single URL, platform-handled routing

Deep linking is the connective tissue between every channel that reaches your users — web, email, push, ads, social, and QR codes. Every entry point should land the user exactly where they intended to go.