Developing APIs using ASP.NET Core is easy and fast, and that is why it is preferred by developers. To begin, open Visual Studio or the .NET CLI and create a new ASP.NET Core Web API project. The controller-based or minimal API template should be selected according to your needs. Then you can specify your data models as C# classes, which are the entities that your API is dealing with. Next, create a database context using Entity Framework Core to allow storing and retrieving data, which usually begins with an in-memory or SQL Server database.
Design API endpoints by either adding controller classes or setting up route handlers that react to HTTP methods such as GET, POST, PUT and DELETE. Apply CRUD operations to control your data. Dependency injection is used to manage services in a clean way. Swagger or Postman are tools that can be used to test your API and explore and confirm your endpoints. Lastly, protect your resources by authenticating and authorizing your API. This gradual process will allow you to create scalable and maintainable APIs fast using ASP.NET Core.