Firebase Dynamic Links Integration in Mobile Apps

Firebase Dynamic Links Integration in Mobile Apps

Imagine a user clicks a promo link in a messenger, but instead of the desired screen, the app's home page opens. Or worse — the link leads to the app store even though the app is already installed. Such context losses reduce referral program conversion by 15–25%. Firebase Dynamic Links solves this, but requires proper configuration.

One of our clients — an e-commerce store with a referral program — saw a 35% increase in referral link conversion and doubled session depth after integrating Dynamic Links. The secret is that the link remembers the target screen even before the app is installed (deferred deep linking).

How Dynamic Links Works and Key Challenges

Firebase Dynamic Links are smart links that direct users to the right app location regardless of whether the app is installed. If the app is installed, it opens a specific screen. If not, it leads to the App Store or Google Play, and after installation delivers the original deep link. Use cases: content sharing, referral programs, email campaigns with context. iOS uses Universal Links, Android uses App Links.

Important: Google is discontinuing support for Firebase Dynamic Links. If you are starting a new project, consider alternatives: Branch.io, Adjust, AppsFlyer, or a custom implementation using App Links + Universal Links + deferred deep linking. If Dynamic Links are already in use, migration is needed.

Typical Integration Mistakes

On iOS, you need to configure apple-app-site-association and the Associated Domains entitlement. On Android, you need an intent-filter with autoVerify="true" and the correct assetlinks.json on the domain. The most common issue: after an app update, Dynamic Links stop working on Android because the signing key hash changes and assetlinks.json is not updated. Or a new applicationId for a debug build is added but not registered in the Firebase Console. Testing must be done on physical devices — simulators do not support all scenarios correctly.

Comparison of Deep Linking Solutions

How to Set Up Dynamic Links in 5 Steps

1. Register a domain for the deep link and associate it with Firebase.
2. Configure the configuration files: apple-app-site-association for iOS and assetlinks.json for Android.
3. Integrate the Firebase SDK into the app and implement incoming link handling.
4. Create a Dynamic Link via the Firebase Console or API.
5. Test on physical devices all scenarios: app installed, not installed, update with transition.

Why Dynamic Links May Stop Working After an App Update?

The main reason is a change in the signing key hash on Android. When you sign a new version with a different key (e.g., a different Keystore), the SHA-256 hash changes. Firebase checks the hash from the console, and if it doesn't match, App Links stop opening your app. Solution: update assetlinks.json on the server with the new hash. On iOS, a similar issue arises with apple-app-site-association if the Bundle ID or server values change.

How to Migrate to Branch.io Without Losing Functionality?

Branch.io is the most feature-rich alternative. It supports deferred deep linking, analytics, and web links. Migration includes:

• Create a Branch account and configure apps.
• Replace the Firebase SDK with the Branch SDK (code integration).
• Migrate domain configuration and links.
• Test all scenarios and run an A/B test comparing with old links.

// Android: Branch initialization
Branch.getAutoInstance(this)

// Handle in Activity
Branch.sessionBuilder(this).withCallback { referringParams, error ->
    referringParams?.getString("+clicked_branch_link")?.let {
        // navigate to target screen
    }
}.withData(this.intent.data).init()

Migrating to a custom implementation — App Links + Universal Links with deferred parameters via your own server — takes more development time but gives full data control. Branch.io provides a ready SDK and analytics, saving up to 20% of the total budget.

What Alternatives to Firebase Dynamic Links Exist?

If Firebase Dynamic Links are being shut down, switch to Branch.io, Adjust, AppsFlyer, or develop a custom solution based on Universal Links, App Links, and deferred deep linking via your own backend. We help choose the best option for your budget and timeline — contact us for a consultation.

What's Included in the Work

We guarantee first-time correct setup of Universal Links and App Links. Experience: over 5 years in mobile development, dozens of deep linking projects.

How We Ensure Results

Our engineers hold Firebase and iOS/Android development certifications. For each project we prepare a custom testing checklist: installed/not installed apps, updates, different OS versions, carrier-dependent interruptions. Get a consultation on your scenario — contact us.

Why Order Integration Now

Dynamic Links simplify user engagement: referral programs with automatic transitions, contextual email campaigns, ad campaigns with precise analytics. Even after Firebase shutdown, functionality can be preserved with other tools. We'll help choose the optimal solution for your budget. Order an audit of your current configuration or turnkey integration.

How to Start Integrating API into a Mobile App?

The request goes out, the response doesn't come, timeout — 30 seconds. The user stares at the spinner. No network — mobile card in the subway. Or the network is there, but the server returns 200 with an HTML error page instead of JSON — and the app crashes on JSONDecoder.decode(). We see such cases on every second project. So integrating API into a mobile app is not just calling an endpoint, but designing a reliable network layer: error handling, caching, offline mode, certificate pinning. Order an audit of your current network layer — we will evaluate the project in 1 day. Our team guarantees a thorough analysis and provides a detailed roadmap.

Standard libraries like URLSession and OkHttp provide basic HTTP clients, but for production you need retries with exponential backoff, status code validation, typed deserialization, and network state monitoring. Without this, the app loses data and users. We have been doing mobile development for 5 years and implemented more than 30 projects with API integration on iOS, Android, and Flutter — from startups to enterprise solutions.

How to Choose a Protocol for API Integration?

REST remains the standard for most projects. But when a profile screen needs 5 fields out of 40, GraphQL eliminates over-fetching and reduces traffic by 30–60%. gRPC is justified for thousands of requests per minute (trading, IoT) — binary serialization is 3–5 times faster than JSON. WebSocket is the only choice for real-time without polling (messages, notifications).

Practical example: For a fintech app, we replaced REST (40 fields) with GraphQL — response size dropped from 12 KB to 2.5 KB, screen render time decreased by 70%. Traffic savings were significant. Our certified iOS and Android developers have deep experience with all these protocols — you can rely on proven solutions.

How to Ensure Reliable Connection and Offline-First?

Users lose network in the subway, elevator, tunnel. A mobile app must work without internet — at least in read-only mode. We implement the offline-first pattern:

1. On screen open, first show data from the local cache (Core Data / Room).
2. Simultaneously perform a network request, update UI after response.
3. If network is unavailable — show cached data and a 'no connection' label.
4. When network is restored, automatically synchronize changes.

For HTTP response caching we use URLCache (iOS) and OkHttp Cache (Android) with Cache-Control support. For structured data — SwiftData / Room. NWPathMonitor / ConnectivityManager.NetworkCallback monitor network state and trigger updates.

REST and Client Library Selection

Alamofire (iOS) — de facto standard for Swift projects. On top of URLSession it adds request chaining, response validation, automatic retry, certificate pinning via ServerTrustManager. AF.request() with .validate() returns an error for any status code outside 200–299. Without .validate(), Alamofire considers 404 and 500 as successful responses. With Swift Concurrency — async version via serializingDecodable.

Retrofit (Android) — annotation-based HTTP client on top of OkHttp. An interface with annotations compiles into implementation. @GET, @POST, @Path, @Query, @Body — declarative API description. OkHttp under the hood: connection pooling, transparent gzip, HTTP/2 multiplex. HttpLoggingInterceptor — logging in debug builds. Authenticator — automatic token refresh on 401.

Ktor (KMM/Flutter) — multiplatform HTTP client. On iOS it works via Darwin engine (URLSession), on Android — via OkHttp. Single code for both platforms with KMM architecture.

GraphQL: When REST Falls Short

REST returns a fixed structure. A profile screen needs name, avatar, email — the server sends 40 fields. Over-fetching. GraphQL solves this: the client requests exactly the needed fields. This is critical for mobile where traffic and parsing time are real constraints. Apollo iOS and Apollo Kotlin generate typed classes from schema: schema.graphql + query files → strict types at compile time. Subscriptions via WebSocket — real-time without polling. Limitation: GraphQL is harder to cache at the HTTP level. Apollo uses a normalized in-memory cache InMemoryNormalizedCache — requests with overlapping data update the cache without duplication.

WebSocket: Real-Time Without Extra Traffic

Polling (setInterval every 5 seconds) — battery and traffic waste. WebSocket is a persistent bidirectional connection. iOS: URLSessionWebSocketTask (native, iOS 13+). Android: OkHttp WebSocket. Mandatory reconnect handling: on onFailure — exponential backoff (1s → 2s → 4s → 8s → max 60s). Socket.IO is an overlay with automatic reconnect, but for new projects native WebSocket is preferable (fewer dependencies).

gRPC: For High-Load Services

gRPC with protobuf — binary serialization: smaller size, faster parsing. grpc-swift for iOS, grpc-kotlin for Android. The protobuf schema compiles to typed classes. Streaming (server-side, client-side, bidirectional) is a native feature. Application threshold: high request frequency (trading, IoT) or critical latency. For regular CRUD, REST is simpler to debug and monitor.

Certificate Pinning and Security

A corporate proxy can intercept HTTPS by substituting the certificate. Certificate pinning prevents this: the app accepts only a specific certificate or public key. Alamofire: ServerTrustManager with PinnedCertificatesTrustEvaluator. OkHttp: CertificatePinner with SHA-256 hash. Apple's App Transport Security documentation recommends pinning certificates for sensitive data. Operational complexity: on certificate rotation, older app versions stop working. Solution — pinning to the CA public key or support multiple pins with a grace period.

What Is Included in the Work

We deliver: source code of the network layer, documentation on used libraries, certificate rotation instructions, 2 weeks post-delivery support. Our experience guarantees that the solution will be stable and maintainable.

Timeline and Cost

Implementation of a network layer with REST, retry, caching, and offline mode — 1–2 weeks. Adding GraphQL or WebSocket — another 1–2 weeks. gRPC — 2–3 weeks, including code generation. The cost is calculated individually after analyzing the API and offline behavior requirements. We will evaluate the project in 1 day — contact us for a consultation. Get a reliable API integration with guaranteed quality.