DDD in .NET 10: Explained

Asela Kotagama

17 min read

·

Oct 24, 2026

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Domain-Driven Design (DDD) can sound intimidating.

And suddenly a simple business requirement feels like a PhD.
But DDD doesn’t have to be complicated. At its core, DDD is about one simple idea:
Put business rules close to the business concepts they belong to.

This article builds a simplified DDD-style Order System using modern .NET 10 and C# 14.
We’ll start with a typical service that becomes messy, then gradually introduce DDD concepts only when they solve an actual problem.

1. The Problem DDD Is Trying to Solve

Imagine you’re building an e-commerce application.

You have an order.

An order can:

• contain products
• add and remove items
• calculate a total
• be submitted
• be cancelled
• require approval
• trigger notifications

A typical application might start like this:

public class Order…