Setup a JWT (JSON Web Token) in an ASP.NET Core Web API, implementing Authentication and Authorization. why it is important for your ASP.NET Core Web API to require authentication with JWT. From project setup to testing this entire process with Postman, Get the good idea about how to setup authentication and authorization in your .NET Core applications with JWT. Authentication with JWT is one of the most secure and most performant ways to secure data transfers between client and server. We’ll not only set up authentication in our ASP.NET Core Web API but we’ll touch on authorization and how different user security roles can access specific resources.