# helix-editor/nucleo

A fast and convenient fuzzy matcher library for rust

Repository: https://github.com/helix-editor/nucleo
Canonical: https://ross.abutalabs.com/products/nucleo
Language: Rust
License: MPL-2.0
License Family: copyleft
Topics: fuzzy-matching, fuzzy-search, performance, rust, text-processing
Last push: 2026-06-24T05:40:57+00:00

## Health v2 (maintenance only)
Score: 59/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 89, release rhythm 8, longevity 80
- inputs: {"age_days": 1133, "days_push": 70, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1492, forks 61 (observed 2026-08-28T04:04:52.645004+00:00)

## What it is
Nucleo is a high-performance fuzzy matcher library for Rust, filling the same role as fzf and skim but with a faster matching algorithm and better Unicode handling. It offers both a fully managed fuzzy picker (nucleo) and a standalone matcher crate (nucleo-matcher), and powers the Helix editor.

## Use cases
- fuzzy find files in a terminal picker
- filter large lists with low-selectivity patterns quickly
- replace fzf or fuzzy-matcher in a Rust application
- fuzzy match non-ASCII and emoji text correctly
- highlight matched grapheme indices in a fuzzy search UI
- build a command palette with fzf-compatible ranking

## When to choose
- you need fzf-quality scoring as an embeddable Rust library
- you match patterns against very large item sets where speed matters
- you need correct Unicode grapheme handling and case insensitivity
- you want a plug-and-play picker like the one in Helix

## When to avoid
- you need a standalone CLI tool rather than a library
- you require a stable 1.0 API for the high-level crate
- your project is not in Rust and you cannot use FFI

## Facets
- artifact type: library
- maturity: active
- function: search-engine, parser
- domain: developer-tools, text-editors, performance
- platform: rust, cross-platform
- tags: fuzzy-matching, fuzzy-finder, fzf-alternative, smith-waterman, unicode-aware, helix-editor, algorithms

## Member repositories
- helix-editor/nucleo (main) score 59

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:52.645004+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 2026-08-30T04:33:30.259905+00:00, confidence not recorded.
  - readme: https://github.com/helix-editor/nucleo (fetched 2026-08-28T04:04:52.645004+00:00, sha a5b67a2636c0)
  - registry_crates: https://crates.io/api/v1/crates/nucleo (fetched 2026-08-29T11:39:06.884193+00:00, sha 9dcdd7bbda3f)
- Data as of 2026-08-30T08:39:29.467469+00:00.