Todo API — C# Clean Architecture

A RESTful To-Do list API built with C# and ASP.NET Core, following Clean Architecture principles with an in-memory database.

Architecture

TodoApp/
├── TodoApp.Domain/          Entities + Repository interface
├── TodoApp.Application/     Business logic (TodoService)
├── TodoApp.Infrastructure/  In-memory repository
├── TodoApp.Api/             HTTP controllers
└── TodoApp.Tests/           Unit and functional tests

Each layer has a single responsibility:

Layer	Responsibility
TodoApp.Domain/	Pure domain model (Todo)
TodoApp.Application/	Repository contract + business logic
TodoApp.Infrastructure/	In-memory repository
TodoApp.Api/	HTTP controllers

API Endpoints

Method	Endpoint	Description	Status
GET	/todos	List all todos	200
POST	/todos	Create a todo	201
GET	/todos/{id}	Get by ID	200
PUT	/todos/{id}	Update a todo	200
DELETE	/todos/{id}	Delete a todo	204

Todo Object

{
  "id": 1,
  "title": "Buy groceries",
  "isCompleted": false,
  "createdAt": "2026-03-12T11:00:00Z"
}

Requirements

• .NET 8+

Setup & Run

cd TodoApp/TodoApp.Api
dotnet run

Server runs on http://localhost:8080.

Testing

# Unit and functional tests
dotnet test TodoApp.sln