Microsoft .NET is the platform that drives the business technology of many of the top corporations in the United States and many other countries. It is the predominant technology used to drive enterprise-scale business technology. There is a high demand across the world for .NET developers in a variety of industries. This course also features web API development; the ability to design and maintain an API is an important toolset for the modern web developer. This course will help you build a fully data-driven REST web API using cutting-edge technology. You will test and troubleshoot using Postman, create a database using Entity Framework Core, set up logging using SeriLog, learn about dependency injection, and API documentation using SwaggerUI. You will understand the REST design principles and authentication using JWT, understand how to use data transfer objects and AutoMapper, manage packages with NuGet manager, and set up GitHub for source control. Learn about API caching, versioning and request rate throttling, and understand .NET 6 workflows, tools and application development. Finally, you will deploy applications and databases on-premises with Internet Information Systems, Microsoft SQL Server, and Microsoft Azure. By the end, you will switch around to Visual Studio for your coding exercise because of your hands-on expertise in examining logic and syntax errors throughout. This will put your newly learned skills to practical use and impress your boss and coworkers. The code files and resource files are updated on the GitHub repository at: https://github.com/PacktPublishing/Ultimate-ASP.NET-5-Web-API-Development-Guide-