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Scalable architecture case study and interview preparation

Case study: evolve a 15-team commerce super-app​

Organize teams/modules around catalog, cart, checkout, orders, identity and media. App shell owns composition/global navigation. Platform teams own build/release, design system, identity/session, observability and sync mechanics as internal products. Domains publish narrow API modules and own implementation/data/conflicts.

Use ID-based navigation contracts, server-authorized session/entitlements, typed configuration registry and fair durable offline scheduler. Enforce dependency graph/API compatibility, startup/binary/build budgets and risk-tiered releases. Multi-brand app modules own package/signing/store identity while semantic tokens/capabilities share features. Enterprise policy overrides user preference only where documented and never replaces server authorization.

Interview questions​

  1. What scales mobile architecture? Independent cohesive ownership plus stable contracts, feedback and operations—not module count alone.
  2. Platform-team purpose? Paved roads that reduce cognitive load; operated as products, not approval bureaucracy.
  3. How version internal contracts? Minimal APIs, additive evolution, API/ABI tests, deprecation/migration and known consumers.
  4. How coordinate navigation/auth/config? App/platform policy with feature-owned integrations and typed boundaries.
  5. How scale offline-first? Share scheduling/idempotency/storage mechanics; domains own conflict semantics.
  6. How govern budgets? Representative measurable allocations, automated/production feedback, owner and expiring exceptions.
  7. How model white-label? Compile-time distribution identity, semantic runtime variation, capability composition and generated release matrix.
  8. What does enterprise management not prove? User authorization, device integrity forever, or secure server action.

Checklist​

  • Domain/module ownership includes incidents, APIs and deprecation.
  • Platform services have SLO/support/adoption and escape strategy.
  • Dependency direction/contracts/events are enforced and versioned.
  • Shared UI/infrastructure limits startup/binary coupling.
  • Navigation, session and config precedence are explicit.
  • Offline fairness, account isolation, conflict and eviction are governed.
  • Performance/build/release budgets have calibrated evidence.
  • Brand and enterprise matrices cover signing, policy, privacy and operations.

Exercises​

  1. Split ownership for a super-app without creating a giant core team.
  2. Design a backward-compatible checkout contract used by five independently releasing apps.
  3. Create governance for a startup regression caused by three platform SDKs.
  4. Threat-model managed-config and audit behavior for a healthcare work-profile app.