Microservices Architecture: Interview Prep Guide

Goal: Broad, systematic coverage — from design thinking to production deployment. Built for senior developers moving into architecture roles.

The Mental Model: Design → Build → Run

graph LR
    A[Foundations] --> B[DDD]
    B --> C[Patterns]
    C --> D[Events]
    D --> E[APIs]
    E --> F[Resilience]
    F --> G[Observability]
    G --> H[Security]
    H --> I[Deployment]
    I --> J[Interview]

Sections at a Glance

# Section Core Topics
01 Architectural Foundations Styles, CAP, Conway's Law, Hexagonal, Onion, Clean
02 Domain-Driven Design Bounded Contexts, Aggregates, Context Mapping, Ubiquitous Language
03 Microservices Patterns Decomposition, Integration, Service Discovery, Caching, Sidecar, Outbox
04 Event-Driven Architecture Kafka, CQRS, Event Sourcing, Saga, Messaging Patterns, DLQ
05 API & Communication REST, gRPC, GraphQL, API Gateway, BFF, Versioning, Configuration
06 Resilience & Reliability Circuit Breaker, Retry, Bulkhead, Timeout, Rate Limiting, Chaos
07 Observability Logs, Metrics, Traces, SLO, OpenTelemetry, DORA Metrics
08 Security OAuth2, JWT, mTLS, Secrets, Zero Trust, Testing Strategies
09 Deployment & Infrastructure Kubernetes, Helm, GitOps, Blue-Green, Canary, Configuration
10 Interview Prep Design scenarios, Trade-offs, ADRs, Spring Boot map
  1. Sections 01–02 — Architecture thinking + DDD (the why behind service boundaries)
  2. Sections 03–04 — Patterns + events (the how of building distributed systems)
  3. Sections 05–09 — Verify and fill gaps in what you already know
  4. Section 10 — Final synthesis through the interview lens

What Architecture Interviews Actually Test

  • Can you decompose a system into coherent services? (DDD)
  • Do you understand distributed system trade-offs? (CAP, eventual consistency)
  • Can you reason about failure scenarios? (Resilience patterns)
  • Do you know how to observe a running system? (Observability)
  • Can you articulate why you'd choose one pattern over another?

Breadth first, depth on demand

This guide is intentionally wide. If a concept feels shallow, that's your signal to go deeper on that specific topic after building the mental map.