# seiflotfy/cuckoofilter

Cuckoo Filter: Practically Better Than Bloom

Repository: https://github.com/seiflotfy/cuckoofilter
Canonical: https://ross.abutalabs.com/products/cuckoofilter
Language: Go
License: MIT
License Family: permissive
Last push: 2024-07-15T13:13:51+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": 4084, "days_push": 779, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1233, forks 120 (observed 2026-08-28T04:04:04.530682+00:00)

## What it is
A Go library implementing cuckoo filters, a space-efficient probabilistic data structure for approximate set-membership queries that supports insertion, lookup, and deletion. It serves as a Bloom filter replacement with comparable or better space efficiency at low false positive rates (~3% with 8-bit fingerprints).

## Use cases
- check if an item is probably in a set without storing the whole set
- replace a bloom filter when I also need to delete items
- build a space-efficient cache membership check
- filter duplicate items in a stream with low memory
- implement approximate set membership with low false positive rate

## When to choose
- you need deletion support that Bloom filters lack
- you want a low false positive rate (<3%) with compact memory usage
- you are working in Go and need a well-tested probabilistic filter

## When to avoid
- you need exact membership answers with zero false positives
- you need very low false positive rates below 0.01% without tuning fingerprint size
- your workload is write-heavy with frequent deletions that could trigger cuckoo eviction failures

## Facets
- artifact type: library
- maturity: stable
- function: search-engine, caching, developer-tools
- domain: databases, performance, developer-tools
- platform: go, cross-platform
- tags: bloom-filter, probabilistic-data-structures, cuckoo-hashing, set-membership, fingerprinting, algorithms

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

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:04.530682+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 2026-08-30T08:22:17.861182+00:00, confidence not recorded.
  - readme: https://github.com/seiflotfy/cuckoofilter (fetched 2026-08-28T04:04:04.530682+00:00, sha ccc84bdd97d0)
- Data as of 2026-08-30T08:39:29.467469+00:00.