Web APIs drive the most popular and powerful Web and mobile apps—making the developer who can build a robust web API a developer that's in demand. Get started creating your own with ASP.NET 9, the open-source framework for Windows, macOS, and Linux.

First, learn about attribute routing, the preferred method of handling HTTP requests in ASP.NET 9. Then learn how to set up controllers, connect them to the data model, set up validation for incoming requests, and configure HTTP responses. Chris Woodruff also shows how to implement CRUD operations on the SQL database server where the data is stored. An advanced development section provides insights on using a repository layer and dependency injection to make your API more abstract and testing projects with tools such as MSTest and xUnit. Demonstrations on optimization and caching show how to improve the performance of your APIs.

Follow along with Chris to learn all these concepts and more, and complete the web API shown in the course: an eCommerce engine for creating and viewing customer orders and assigning orders to sales reps.

Prerequisites
It is strongly recommended that you have some knowledge of the following:
• C# and .NET 9
• LINQ
• Entity Framework Core
• Microsoft SQL Server
• ASP.NET MVC
You will need the following software installed on your machine.
• Your favorite .NET IDE
• .NET 9 SDK
• Microsoft SQL Server or Windows Azure or AWS account for MSSQL
• An HTTP debugging tool like Fiddler or Postman
• Git

Takeaways
• Learn about ASP.NET 9, where it came from and how to start using it for web and API development
• Learn how to use ASP.NET 9 Web API's built-in dependency injection for more robust and easier-to-maintain projects.
• Learn how to create routes for your API calls with the MVC pattern.
• Learn how to work with domain models and data in your API, along with caching.
• Learn how to test and debug your ASP.NET 9 Web API solution.
• Learn advanced architecture techniques in ASP.NET 9 Web API