Most .NET developers rely on basic authentication patterns that break down in modern distributed systems. Simple role-based authorization and cookie-based authentication can't handle multi-tenant SaaS applications, microservices architectures, or mobile clients securely. The result is either over-engineered custom solutions or security vulnerabilities that expose sensitive data.

This talk demonstrates OAuth 2.0 and OpenID Connect implementation in .NET, focusing on policy-based authorization, zero-trust patterns for microservices and token management strategies. We'll build working examples of attribute-based access control (ABAC), service-to-service authentication, and cross-platform token flows. You'll see techniques for debugging authentication failures and how to security patterns using ASP.NET Core's authorization framework.

If you are a .NET developer working on web APIs, microservices, or multi-client applications who need to move beyond basic [Authorize] attributes, this talk is for you. Whether you're building SaaS platforms, securing service-to-service communication, or integrating with third-party identity providers, you'll gain immediately usable code patterns and architectural strategies for production-ready authentication systems.