1. Anti-Corruption Layer intermediate

    A card platform integrates with a network whose data model and semantics differ fundamentally from its own. Where should the translation live and what discipline does it require?

    2 min answer marqetaanti-corruption-layerintegrationmodel
  2. Anti-Corruption Layer intermediate

    A new service must integrate with a legacy system whose data model is entangled and poorly named. What does an anti-corruption layer actually do, and how do you know it is working?

    2 min answer anti-corruption-layerdddlegacyintegration
  3. Anti-Corruption Layer intermediate

    A platform integrates retailer systems with inconsistent models. What does an anti-corruption layer prevent, and where does it belong?

    2 min answer anti-corruption-layertranslationmodelspartners
  4. Anti-Corruption Layer intermediate Multiple choice

    A team integrates a vendor CRM whose customer model contradicts theirs. Six months later vendor field names and status codes appear throughout the codebase. What was missing and what is the fix now?

    2 min answer acldddintegrationlegacy
  5. API Gateway intermediate

    An API gateway has accumulated authentication, rate limiting, routing, response transformation, request validation and some business logic. Which of these belong there?

    2 min answer razorpaygatewaycross-cuttingcoupling
  6. Architecture Patterns intermediate

    Design a URL shortener handling 100 million new links per month and 10 billion redirects. Where is the real difficulty?

    2 min answer system-designcachingscalingstorage
  7. Architecture Patterns intermediate Multiple choice

    Orders must trigger inventory reservation, a confirmation email, an analytics record and a fraud check. Queue, topic, or both — and what breaks if you choose wrong?

    2 min answer pubsubqueuesevent-drivencompeting-consumers
  8. Backend for Frontend intermediate

    A platform has a backend-for-frontend per client, and they have diverged with duplicated logic. Is BFF still the right pattern?

    2 min answer bffduplicationownershipshared-logic
  9. Backend for Frontend intermediate

    A product runs on web, iOS, Android and a television app. The shared API team is the bottleneck for every client change. Design the fix.

    3 min answer bffapi-designnetflixownership
  10. Backend for Frontend intermediate

    A quick-commerce platform serves a mobile app, a web app and a partner API from the same services. When does a backend-for-frontend earn its place?

    2 min answer zeptobffaggregationclients
  11. Backend for Frontend intermediate

    A travel platform with Booking.com's catalogue breadth replaces nine client-side calls with one backend-for-frontend call that fans out to the same nine services. Mobile p99 improves by 40% on the first day. Each of the nine services holds 99.9% availability. What has the team given up, and when does the bill arrive?

    3 min answer bffaggregationavailabilitypartial rendering
  12. Backend for Frontend intermediate

    Several client applications with different needs consume the same backend. When is a backend-for-frontend justified, and when does it become an unowned distributed monolith?

    2 min answer bffapi-designclientsownership