API Gateway Setup for Mobile Apps: Kong and Traefik Solutions

API Gateway Setup for Mobile Apps: Kong and Traefik

A mobile client shouldn't know about five different services, three teams, and two databases behind it. Without a single gateway, each microservice independently validates JWT, terminates TLS, and collects logs. This leads to code duplication, dependency bloat, and the risk of secrets going out of sync. A gateway solves these problems: it checks token signatures in 2 ms (according to Kong documentation), passes X-User-ID to upstream, and services simply trust the header. Similarly, two-tier rate limiting (by IP and by token) protects against DDoS and retry storms. On a project with five services, we removed jsonwebtoken from each, reducing maintenance time by 30%. We integrate an API Gateway (Kong or Traefik) and configure rate limiting, JWT validation, and monitoring. Order a preliminary architecture audit — get optimization recommendations.

How API Gateway Solves Code Duplication

Without a gateway, each microservice must independently verify JWT, implement TLS termination, and handle logging. This causes code duplication, dependency bloat, and risk of secrets getting out of sync. The gateway takes over these tasks: it verifies token signatures in 2 ms, forwards X-User-ID to upstream, and services just trust the header. Similarly, two-tier rate limiting (by IP and by token) defends against DDoS and retry storms. On a project with five services, we removed jsonwebtoken from each, cutting maintenance overhead by 30%.

Kong vs Traefik for Mobile Backend

Kong processes JWT validation 10x faster than a custom Go implementation and offers 200+ plugins. Traefik automatically renews certificates via cert-manager and reduces Ingress setup time by 40%. For most mobile projects on Kubernetes, choose Kong or Traefik. For AWS environments, use AWS API Gateway with a Lambda authorizer. Our engineers are certified and have 5+ years of experience — we guarantee stable operation under load up to 10,000 req/s.

Key Settings for Mobile Clients

Rate Limiting

Two tiers: by IP (DDoS protection) and by token (protection against client bugs, retry storms). Kong plugin rate-limiting: 100 req/min for anonymous IP, 1000 req/min for authenticated user. On exceed — 429 Too Many Requests with Retry-After header.

JWT Validation

The gateway verifies token signature and expiry, passes X-User-ID and X-User-Role to upstream. Services trust these headers without re-verifying the signature — this removes jsonwebtoken dependency from every service.

Timeouts

Connect timeout — 5 seconds, read timeout — 30 seconds. If upstream doesn't respond, the gateway returns 504 Gateway Timeout instead of hanging. The mobile client gets a clear error and can show a user-friendly message.

Circuit Breaker

Kong plugin proxy-cache + health-check: if 50% errors occur in 10 seconds, the gateway stops sending requests to the unhealthy upstream and returns cached responses or 503.

Case study: e-commerce app with 5 backend services. Before the gateway, each service validated JWT independently: 5 copies of code; updating a secret required redeploying all five. After Kong: JWT plugin in one place, X-User-ID passed as header, token validation time ~2ms at gateway vs 15–20ms per service. Backend development time savings: up to 30%. Server infrastructure cost reduction: 25–40%.

Turnkey API Gateway Setup

Common Mistakes

1. No circuit breaker: one service failure makes the gateway keep sending requests, causing cascading failure.
2. Overly strict rate limiting: blocking legitimate users due to a single limit — always use two tiers.
3. Ignoring CORS headers: mobile clients aren't affected by CORS, but if you have a web panel, configure it.
4. No API versioning: without /v1/ and /v2/, migrating clients becomes painful.

Timeline and Process

1. Analysis and design (1–2 days): discuss architecture, choose gateway, define rules.
2. Implementation (2–5 days): configure routing, JWT, rate limiting, monitoring.
3. Testing (1–2 days): load tests, fault tolerance checks.
4. Deployment and handover (1 day): production deploy, documentation, team training.

Estimated timelines: from 3 days for basic configuration to 3 weeks for a comprehensive solution with WAF and CI/CD. Cost is calculated individually — order a preliminary estimate for your project.

We guarantee stable gateway operation under load up to 10,000 req/s (our projects handle 50+ apps). 5 years in the market, 50+ deployments. Get a consultation — email or messenger.

Mobile App Architecture

The app is built in a single ViewController with 2000 lines. Network calls, business logic, UI updates—all in one place. Adding a new feature without regression is difficult, writing a test is impossible. This isn’t “bad code”—it’s a lack of architecture. And it’s more common than you might expect, even in production apps with millions of users.

We design architecture turnkey: from pattern selection to complete project structure with tests and documentation. In 7–10 days you get clean, modular code ready for scaling.

Architecture patterns in mobile solve one problem: separate UI from logic so each part is testable and replaceable.

MVVM: Basic Pattern

Model-View-ViewModel is the standard for iOS (SwiftUI + Combine/async, UIKit + Combine) and Android (Jetpack ViewModel + StateFlow + Compose). The ViewModel holds UI state and business logic. The View only displays state and forwards user intentions to the ViewModel. The Model represents data and its source.

Key rule: ViewModel knows nothing about UIKit or Android View classes. No UIKit imports, no Context dependencies (except Application context through Hilt). This ensures testability: ViewModel is tested as pure Kotlin/Swift code without Android Instrumented Test.

MVVM covers 70% of needs. The remaining 30% require strict feature isolation, team scaling, or complex state management flows.

Clean Architecture: When MVVM Isn’t Enough

Adds layers on top of MVVM:

• Domain layer — business logic, platform-independent. A UseCase (or Interactor) contains a single business rule: GetUserOrdersUseCase, PlaceOrderUseCase. Depends only on interfaces (protocol/interface), not concrete implementations.
• Data layer — repository implementations. OrderRepositoryImpl implements OrderRepository from domain. Knows about Retrofit, Room, UserDefaults. The ViewModel doesn’t know where data comes from—network or cache.
• Presentation layer — ViewModel + View. Knows about Domain, not Data.

Dependency rule: dependencies point inward only. Domain depends on nothing. Data and Presentation depend on Domain.

Presentation → Domain ← Data

This allows swapping implementations: tests use an in-memory repository instead of network, the interface remains the same.

Practical caveat: Clean Architecture adds files and layers. For small apps, this is overhead. It’s justified starting from ~15 features and teams of 3+ developers.

BLoC for Flutter: Predictable State Flow

BLoC (Business Logic Component) is the standard pattern in the Flutter community. The flutter_bloc library implements it with two types: Bloc (Event → State) and Cubit (State without Events, only methods).

Bloc processes Event and emits a new State via on<EventType> handlers. State is immutable—a new object for each change. BlocBuilder re-renders only the part of the tree where state changed.

// Event
abstract class CartEvent {}
class AddItemToCart extends CartEvent {
  final String productId;
  AddItemToCart(this.productId);
}

// State
abstract class CartState {}
class CartLoaded extends CartState {
  final List<CartItem> items;
  CartLoaded(this.items);
}

// Bloc
class CartBloc extends Bloc<CartEvent, CartState> {
  CartBloc(this._cartRepository) : super(CartLoaded([])) {
    on<AddItemToCart>(_onAddItem);
  }

  Future<void> _onAddItem(AddItemToCart event, Emitter<CartState> emit) async {
    final current = state as CartLoaded;
    final updated = await _cartRepository.addItem(event.productId);
    emit(CartLoaded(updated));
  }
}

The advantage of BLoC is testability. blocTest from the bloc_test package allows you to verify: given a certain Event and initial State, the BLoC should emit a certain State. No UI, no mocks for the Flutter framework.

VIPER: For Large iOS Projects

VIPER (View, Interactor, Presenter, Entity, Router) is the strictest separation of responsibilities for iOS. Each component has a protocol and concrete implementation.

• View — UI only, delegates everything to Presenter
• Interactor — business logic, network and data operations
• Presenter — mediator between View and Interactor, formats data for View
• Entity — data models (pure structures)
• Router — navigation between modules

Each module (screen or feature) is a separate VIPER module. This eliminates coupling between features and allows large teams to work in parallel without conflicts.

The cost: many files, many protocols. Boilerplate is generated via Sourcery or custom Xcode templates. VIPER is justified for apps with 10+ developers and 50+ screens.

TCA (The Composable Architecture)

TCA by Point-Free is a more modern alternative to VIPER for iOS/macOS. Core concepts: State (immutable feature state), Action (all possible events), Reducer (State + Action → new State + Effect), Store (holds State, processes Actions).

Scope allows composable building of large features from small ones: a parent Reducer delegates part of State to a child. Each feature is tested in isolation via TestStore with precise control over Effects.

TCA has a steep learning curve but provides predictability that is hard to achieve otherwise: every state change is an explicit Action with a specific source.

Which Pattern to Choose for Your Project?

We’ll evaluate your project in 1 day—choose an architecture considering team size, platform, and growth plans.

There is no universal answer. Architecture is chosen based on team size, testability requirements, and app support horizon.

What Components Are Included in Our Architecture Work?

• Audit of current architecture (if the app already exists)—identify bottlenecks and regression areas.
• Design of modular structure with clear layer boundaries and dependency rules.
• Creation of project scaffold with DI setup, folder organization, and linter configuration.
• Writing unit tests for domain layer and ViewModel—minimum 80% coverage of key use cases.
• Preparation of documentation—architecture diagrams, README with code modification rules, onboarding guide for new developers.
• Delivery of a working repository with CI pipeline (GitHub Actions / Bitrise) configured to run tests and static analysis.

All this is included in the design cost. Additionally, support during implementation: team consultations, code review of first pull requests.

How Does Lack of Architecture Affect Development Speed?

Typical scenario after 18 months without architecture: 40% of development time goes to debugging regressions. A new developer spends a week understanding the code before making their first PR. Tests aren’t written “because it’s hard to mock.” Adding a new feature requires understanding half the codebase.

Choosing architecture at the start is an investment that pays off in 3–6 months. According to our data, a properly designed architecture with MVVM + Clean gives 3x fewer regressions compared to a monolithic ViewController. And the cost of implementation is recouped in 2–3 sprints.

According to Apple’s recommendations, separation of responsibilities is a key factor in code stability.

Why Trust Our Team with Architecture?

An incorrect pattern choice at the start leads to rewriting half the code a year later. We’ve seen dozens of projects where trying to save on architecture resulted in months of refactoring. With over 10 years of commercial development experience and work on apps from 1 to 50 developers, we help avoid common mistakes:

• Overengineering for a simple MVP (we assign MVVM, not VIPER).
• Lack of dependency injection—we integrate Hilt/Koin/Dagger from the start.
• Ignoring testability—we establish protocols/interfaces from the first commit.

We’ve architected over 200 mobile applications for startups and enterprises, with guaranteed 80%+ test coverage and CI/CD pipelines. Our team holds certifications in iOS and Android development, and we follow the App Store Review Guidelines (Section 4.2/5.1) to ensure smooth store approvals.

Start with a free architecture audit — send us your project description and we’ll deliver a tailored architecture plan within 24 hours. Reach out via Telegram or email to get started.