# zesterer/chumsky

[Chumsky has moved to Codeberg!] Write expressive, high-performance parsers with ease.

Repository: https://github.com/zesterer/chumsky
Canonical: https://ross.abutalabs.com/products/chumsky
Homepage: https://codeberg.org/zesterer/chumsky
Language: Rust
License: MIT
License Family: permissive
Topics: parser, parser-combinators, context-free-grammar, errors, recursive-descent-parser, peg, lexing, parsing
Archived: true
Last push: 2026-03-27T00:01:28+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 74, release rhythm 8, longevity 100
- inputs: {"age_days": 1880, "days_push": 160, "days_rel": 529, "gap_med": null, "n_releases_24m": 1}
- flags: archived
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4540, forks 212 (observed 2026-08-28T04:08:53.106413+00:00)

## What it is
Chumsky is a Rust parser-combinator library for writing expressive, high-performance parsers with rich error diagnostics and recovery. It supports context-free grammars, zero-copy parsing, Pratt expression parsing, and no_std environments.

## Use cases
- write a parser for a programming language compiler
- parse configuration files in Rust
- parse binary protocols at the networking layer
- build a lexer and parser for a DSL
- parse expressions with operator precedence
- validate complex input with friendly error messages
- generate railroad diagrams for a grammar

## When to choose
- you're writing a compiler or interpreter frontend in Rust
- you need expressive combinators with good error recovery and diagnostics
- you want zero-copy parsing or no_std/embedded support
- you need Pratt parsing or left recursion support

## When to avoid
- you need maximum parsing speed above all else (hand-written or LALR parsers may be faster)
- you're not using Rust
- you want a grammar-file-based parser generator rather than combinators in code

## Facets
- artifact type: library
- maturity: active
- function: parser, developer-tools
- domain: parsers, programming-languages, developer-tools
- platform: rust, cross-platform, embedded
- tags: parser-combinators, peg, recursive-descent, error-recovery, zero-copy, no-std, pratt-parsing, lexer

## Member repositories
- zesterer/chumsky (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:53.106413+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 2026-08-29T18:20:09.933500+00:00, confidence not recorded.
  - readme: https://github.com/zesterer/chumsky (fetched 2026-08-28T04:08:53.106413+00:00, sha 40314a4a4d6c)
- Data as of 2026-08-30T08:39:29.467469+00:00.