Boost.Bloom is a header-only C++ library for efficient probabilistic set membership testing.
It allows you to check whether an element might be in a set, with minimal memory overhead and no false negatives, ideal for high-throughput scenarios like caching, deduplication, and indexing.
The filter is highly space-efficient, and can dramatically reduce the cost of negative lookups in systems where accessing the full data set is expensive.
Repo: https://github.com/boostorg/bloom
Docs: https://boost.org/libs/bloom