Lessons Learned from Scaling Up Cloudflare’s Anomaly Detection Platform

What this post added

This post details the development and scaling of Cloudflare's Anomaly Detection platform, a key component of its Bot Management system. It explains the underlying technology (HBOS, ClickHouse, Redis, HyperLogLog), the platform's architecture (microservices), and the lessons learned during its evolution from a monolithic service to a highly scalable system capable of processing 500K requests per second. Key contributions include insights into optimizing Redis performance (PFMERGE, recency register, key encoding) and the strategic shift to a microservices architecture to improve resilience and reduce load on shared dependencies.