gateway-security

JWT authentication for an ASP.NET Core gateway is configured using the AddJwtAuthentication extension, which sets up JWT Bearer authentication from the Jwt section of your application configuration. This ensures consistent token validation across gateway endpoints.

Policy-based authorization in a microservices gateway is enforced by registering the AddPolicies extension, which maps custom requirements and ApiScope-based access to specific controllers and actions. This centralizes security logic and reduces misconfigurations across services.

Role-based and policy-based authorization can be used together in ASP.NET Core by applying flexible integration patterns. You can secure endpoints using default [Authorize], [Authorize(Policy = ...)] for custom requirements, or [Authorize(Roles = ...)] for role-based access.

Custom authorization handlers are needed for gateway endpoints when enforcing specific ApiScope-based access or custom policy requirements that standard role checks cannot cover. They provide reusable, testable security primitives for evaluating user claims.

This JWT gateway security approach works without additional dependencies, relying entirely on built-in ASP.NET Core components. It provides centralized security primitives, policy constants, and extension methods to wire authentication directly in startup.

A gateway needs centralized JWT authentication instead of service-level security to ensure a unified security posture across microservices. Centralizing token validation and policy enforcement reduces misconfigurations and security gaps in distributed environments.