Design an end-to-end spam detection system

Design an end-to-end email spam detection system. Requirements Real-time scoring with p99 latency under 50 ms. Minimize false positives (target precision of at least 98% on hard blocks) while keeping recall high. Adversaries evolve their tactics over time. Describe Problem framing and labeling: ham vs. spam, graymail, and handling of noisy or weak labels and delayed abuse reports. Features and representations: character and word n-grams, sender/domain/IP reputation, URL…