Overview

Want to master Domain-Driven Design through practical examples? This by-example guide teaches DDD through annotated code and diagram examples organized by complexity level.

What Is DDD By-Example Learning?

DDD by-example learning is a pattern-first approach where you learn through practical implementations of DDD concepts rather than narrative explanations. Each example shows:

Domain modeling - How to model complex business domains
Tactical patterns - Entities, value objects, aggregates, repositories, services
Strategic patterns - Bounded contexts, context mapping, domain events
Working code - Runnable examples showing DDD in practice

This approach is ideal for developers and architects who want to apply DDD principles to real-world software systems.

Learning Path

The DDD by-example tutorial guides you through examples organized into three progressive levels, from basic building blocks to complex strategic patterns.

Coverage Philosophy

This by-example guide provides practical coverage of DDD through annotated examples. The focus is on applying DDD patterns, not just understanding theory.

What's Covered

Building blocks - Entities, value objects, aggregates, domain events
Tactical patterns - Repositories, factories, services, domain events
Strategic patterns - Bounded contexts, context maps, anti-corruption layers
Domain modeling - Ubiquitous language, aggregates design, event storming
Integration patterns - Shared kernel, customer-supplier, conformist

What's NOT Covered

Deep DDD philosophy (see by-concept tutorials for conceptual understanding)
Framework-specific implementations (examples use language-agnostic patterns)
Event sourcing and CQRS advanced patterns (separate tutorials)

Prerequisites

Object-oriented programming experience
Understanding of software design patterns
Experience with business domain modeling

Structure of Each Example

Every example follows a consistent five-part format:

Brief Explanation: What DDD concept the example demonstrates (1-3 sentences)
Optional Diagram: Mermaid diagram when concept relationships are complex
Heavily Annotated Code: Self-contained, runnable implementation with // => annotations explaining values, states, and effects
Key Takeaway: The core DDD principle to retain (1-2 sentences)
Why It Matters: Real-world business impact and production system context (50-100 words)

This structure delivers both implementation detail and business reasoning in each example.