# Module 3: Boundaries

## Overview

In this module, you'll learn to define what's inside your system vs. what's outside (the environment). Understanding boundaries is crucial for clear ownership, risk management, and integration planning.

## Learning Objectives

By the end of this module, you'll be able to:

- Define system boundaries clearly
- Model internal vs. external components
- Identify and document dependencies
- Create bounded contexts for services
- Plan integrations at boundaries

## Lessons

- [Lesson 1: Understanding Boundaries](lesson-1.md) - What boundaries are and why they matter
- [Lesson 2: Internal vs External](lesson-2.md) - Differentiating and marking boundary elements
- [Lesson 3: Crossing Boundaries](lesson-3.md) - Modeling integrations and dependencies

## Prerequisites

- Completed [Module 2: Parts and Relationships](../module-2-parts-relationships/module-overview.md)

## Time Investment

Approximately 1-1.5 hours to complete all lessons and exercises.

## What's Next

After completing this module, you'll learn about [Module 4: Flows](../module-4-flows/module-overview.md).
