A HyperLogLog is a probabilistic data structure that estimates the cardinality of set. In this explainer, we'll see how to build a privacy-preserving traffic heat map for the city of San Francisco. We'll learn the PFADD and PFCOUNT commands along the way! Links: Redis University → Redis Labs → HyperLogLog Docs → #hyperloglog Need a Redis cluster now? Sign up for a free Redis Cloud Essentials account → Join our discord server →