Part 3 — Architecture & Patterns

Composing building blocks into real systems. Where engineering meets art.

Prerequisites: Part 2 — Building Blocks (all chapters)

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Overview

Part 3 covers the architectural patterns that compose individual building blocks into real distributed systems. You'll learn both the "happy path" designs and the cross-cutting concerns (security, observability) that make systems production-ready.

By the end of Part 3, you'll be able to:

• Design microservices with proper service discovery and API gateways
• Apply event-driven architecture and CQRS patterns
• Implement distributed consensus and data replication strategies
• Build secure, reliable systems with proper authentication and rate limiting
• Set up observability with metrics, logs, traces, and SLOs

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Chapters

Chapter 13 — Microservices

Service discovery, API gateway, circuit breaker, saga pattern, service mesh. From monolith to microservices.

Chapter 14 — Event-Driven Architecture

Event sourcing, CQRS, event bus, choreography vs orchestration, domain events.

Chapter 15 — Data Replication & Consistency

Consensus protocols (Raft, Paxos), leader election, quorum reads/writes, conflict resolution.

Chapter 16 — Security & Reliability

OAuth2/JWT, rate limiting, DDoS mitigation, circuit breakers, graceful degradation, disaster recovery.

Chapter 17 — Monitoring & Observability

Three pillars (metrics, logs, traces), SLIs/SLOs/SLAs, error budgets, distributed tracing, alerting.

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Time Estimate

~6 hours of focused reading and practice.