In this article, we will implement AspNetCore Identity Authentication into an existing Blazor Server app. Microsoft AspNetCore Identity Library: AspNetCore Identity: Built-in login functionality library that supports authentication of all different .NET applications. Provides rich authentication UI pages and customizable as well. Adoptable for external authentication providers like 'Google', 'Facebook', 'Outlook'. Can be integrated with other authentications like 'IdentityServer4', 'Azure Active Directory', 'Azure Active Directory B2C(Azure AD B2C)'. Blazor Server Project With No Authentication: Our goal is to implement the AspNetCore Identity Authentication manually into an existing Blazor Server application(the project doesn't have authentication). So to accomplish our demo let's create a Blazor server application without any authentication. We can use either Visual Studio 2022 or Visual Studio Code(using .NET CLI commands)