How to Implement API DDoS Protection: Architecture for Mitigating Multi-Vector Attacks Without Blocking Legitimate Clients

This article addresses API services such as app backends, payment gateways, and AI model interfaces, analyzing the characteristics of multi-vector DDoS attacks combining Layer 4 traffic floods and Layer 7 concurrency. It explores how to implement API DDoS protection without affecting legitimate clients and callback notifications, using Anycast scrubbing, intelligent WAF exception rules, TLS 1.3 0-RTT acceleration, and fixed peak billing architecture.