Adaptive Rate Limiting Cascade Failures: Why Multi-Carrier API Throttling Breaks When Single-Carrier Solutions Scale to Production
When FedEx, DHL, and UPS APIs all throttle simultaneously during Black Friday volume, theoretical improvements disappear fast. Between Q1 2024 and Q1 2025, average API uptime fell from 99.66% to 99.46%, resulting in 60% more downtime year-over-year. Dynamic rate limiting improves API performance by up to 42% under