Pinterest runs a multi-layered automated system to detect and remove spam content and fake accounts. The system operates in real time — flagging suspicious behavior within seconds of it occurring — as well as in scheduled batch scans of all accounts and content. Pinterest's transparency reports document over one million account deactivations for spam in a single six-month period.

The system consists of several interconnected components: a real-time rules engine called Guardian that monitors activity streams and applies automated detection rules; deep neural network classifiers that score outbound links for spam characteristics; a graph-based label propagation system that identifies clusters of accounts behaving in coordinated ways; and a time-series anomaly detection layer that flags sudden spikes in suspicious activity and can automatically generate temporary blocking rules during spam attacks. Account takeover protection (identifying when a legitimate account has been hijacked) is also included. Pinterest's data infrastructure processes over 800 billion messages per day to support these systems.