In the world of large-scale data, asking simple questions like “Have I seen this before?” needs to be fast and efficient, without eating up all your memory. That’s where probabilistic data structures like Bloom filters and Cuckoo filters come in.

In this talk, we’ll explore how Valkey, high-performance, open-source fork of Redis, uses Bloom, and Cuckoo filters to help developers tackle membership tests without large footprints. We will explore the fundamentals of what these filters are, how they work, what makes them memory-efficient, why they occasionally lie, and when to choose one over the other.

We’ll cover some real-world use cases, practical tips for implementing, and tuning these filters in Valkey. Whether you’re building a caching layer, or fighting duplicate data, you’ll leave with a clear understanding of how to get the most out of these clever data structures.