Create a Web API with ASP.NET Core and Visual Studio for Windows

This tutorial builds a web API for managing a list of "to-do" items when a user interface (UI) isn't created.

There are 3 versions of this tutorial:

Overview

This tutorial creates the following API:

API	Description	Request body	Response body
GET /api/todo	Get all to-do items	None	Array of to-do items
GET /api/todo/{id}	Get an item by ID	None	To-do item
POST /api/todo	Add a new item	To-do item	To-do item
PUT /api/todo/{id}	Update an existing item	To-do item	None
DELETE /api/todo/{id}	Delete an item	None	None

The following diagram shows the basic design of the app.

The client is whatever consumes the web API (mobile app, browser, etc.). This tutorial doesn't create a client. Postman or curl is used as the client to test the app.
A model is an object that represents the data in the app. In this case, the only model is a to-do item. Models are represented as C# classes, also known as Plain Old C# Object (POCOs).
A controller is an object that handles HTTP requests and creates the HTTP response. This app has a single controller.
To keep the tutorial simple, the app doesn't use a persistent database. The sample app stores to-do items in an in-memory database.

Click here for the full explanation with Web API Example.