What is Hexagonal Architecture and Why You Should Care

If you’ve ever heard of "clean architecture", "DDD", or "hexagonal architecture" and felt lost, this post is for you!

Today, I’ll explain in a simple and straightforward way what Hexagonal Architecture (also known as Ports and Adapters) is and how it can help you write more organized and scalable code.

What is Hexagonal Architecture?

Hexagonal Architecture is a design pattern that separates your system into clear layers. The main goal is to keep your business logic independent from external details like databases, frameworks, external APIs, etc.

Visually, this architecture is represented by a hexagon, but the most important aspect to understand is how it isolates the core of your application from external influences.

How Does It Work?

In a traditional application, you may have tightly coupled components. For example, your business logic might directly depend on a specific database or framework. This can create a mess and make your application hard to maintain or scale.

In Hexagonal Architecture, the idea is to separate concerns into clear boundaries:

1. Core (Business Logic): This is the heart of your application. It's where your domain logic lives — the part of your code that does the actual work.

2. Ports: These define interfaces that allow communication with the outside world. It’s like defining a contract for how external systems can interact with your core logic.

3. Adapters: These are the implementations of the ports. They "adapt" the data from external systems (like databases, APIs, or UI frameworks) to the format your core logic understands, and vice versa.

Why Should You Care?

Here are a few reasons why Hexagonal Architecture is great, especially for beginners:

• Decoupling: By separating the core logic from the external systems, it becomes much easier to swap technologies (e.g., changing a database or switching frameworks) without affecting your core logic.

• Testability: Since your core logic is independent, you can test it in isolation. You don’t need a real database or a framework running to test your business logic.

• Maintainability: It’s easier to maintain a clean separation of concerns. Your code will be easier to understand, extend, and modify over time.

Example Breakdown

Let’s say you’re building a simple API. Here’s how it might look in Hexagonal Architecture:

• Core: Your business logic for handling user registration.
• Port: An interface that defines how the registration process can be triggered (e.g., registerUser()).
• Adapter: An implementation of the registerUser() port that connects to an HTTP endpoint or a CLI command.

When you need to change the way you interact with external systems (say, changing from a SQL database to a NoSQL one), you only need to modify the adapter — your core logic stays the same.

Final Thoughts

If you’re building something small, Hexagonal Architecture might feel like overkill. But as your project grows, this pattern helps in keeping your codebase clean and scalable.

Give it a try the next time you're designing a new system. Even if you don't implement the full hexagonal architecture, applying its principles of separation and decoupling can make your life a lot easier!