# efficient/cuckoofilter

Repository: https://github.com/efficient/cuckoofilter
Canonical: https://ross.abutalabs.com/products/efficient-cuckoofilter
Language: C++
License: NOASSERTION
License Family: other
Last push: 2021-11-12T19:47:35+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 4849, "days_push": 1755, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1012, forks 175 (observed 2026-08-28T04:03:13.357310+00:00)

## What it is
A C++ library implementing cuckoo filters, a space-efficient probabilistic data structure for approximate set-membership queries that supports deletion, serving as a Bloom filter replacement. It is based on cuckoo hashing and stores key fingerprints, achieving compact space at low false positive rates.

## Use cases
- check if an item is probably in a set without storing the full set
- replace a Bloom filter when items need to be deleted
- build a space-efficient membership filter with low false positive rate
- track seen items in a stream with dynamic add and remove
- benchmark probabilistic filters for speed and space

## When to choose
- you need deletions from an approximate membership structure without counting Bloom filter overhead
- you need low false positive rates (<3%) with compact memory usage
- you are working in C++ and want a small, benchmarked filter implementation

## When to avoid
- you need exact membership answers with zero false positives
- you need a Bloom filter in another language or with bindings
- your false positive tolerance is high and a simpler Bloom filter suffices
- you need an actively maintained project with recent releases

## Facets
- artifact type: library
- maturity: maintenance
- function: search-engine, caching, developer-tools
- domain: databases, performance, developer-tools
- platform: cpp, cross-platform, windows
- tags: cuckoo-filter, bloom-filter, probabilistic-data-structure, set-membership, header-only, algorithms, linux, macos

## Member repositories
- efficient/cuckoofilter (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:13.357310+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T07:11:44.773431+00:00, confidence not recorded.
  - readme: https://github.com/efficient/cuckoofilter (fetched 2026-08-28T04:03:13.357310+00:00, sha b02a526896b8)
- Data as of 2026-08-30T08:39:29.467469+00:00.