Imagine needing to check if something is in a huge collection without storing the entire collection in memory. Bloom filters offer a clever solution to this problem. A Bloom filter is a space-efficient probabilistic data structure for set membership tests – it can quickly tell you if an item is definitely not in a set or if it is probably in the set. In other words, false negatives are impossible (it never misses an item that was added), but it can sometimes return a false positive (claim an item is in the set when it isn’t, due to its probabilistic nature)