Explore the intricacies of securing API-first websites in this comprehensive conference talk. Delve into practical implementations of Identity Server 4 within an ASP.NET Core app, focusing on token server functionality. Learn how to effectively secure your API, integrate an Angular Single Page Application (SPA), and extend API access to third-party developers using OAuth. Gain hands-on experience through numerous demonstrations, covering Entity Framework and ASP.NET Identity for robust security measures, ASP.NET Core MVC for API development, and Angular for SPA creation. This 63-minute session provides valuable insights for developers looking to enhance their understanding of modern web application security and integration techniques.