Why API Gateways Aren’t Good for East-West Traffic

API gateways are designed for north-south traffic (external client-to-service communication) but create anti-patterns when used for east-west traffic (internal service-to-service communication). Using gateways internally introduces unnecessary latency through hairpin routing, creates tight coupling between services, and establishes a single point of failure that defeats the purpose of distributed architectures. For internal communication, service meshes, asynchronous messaging brokers, or smart client libraries provide better resilience, performance, and fault isolation. The recommended approach is using API gateways at the edge for external traffic management while employing service meshes or alternatives for internal service communication.