# CommonMark

CommonMark parsing and rendering library and program in C

Repository: https://github.com/commonmark/cmark
Canonical: https://ross.abutalabs.com/products/commonmark
Language: C
License: NOASSERTION
License Family: other
Last push: 2026-08-12T15:48:31+00:00
Link (homepage): http://commonmark.org

## Health v2 (maintenance only)
Score: 77/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 97, release rhythm 38, longevity 100
- inputs: {"age_days": 4238, "days_push": 21, "days_rel": 200, "gap_med": null, "n_releases_24m": 1}
- flags: no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2022, forks 676 (observed 2026-08-28T04:06:06.390067+00:00)

## What it is
CommonMark is a rationalized, unambiguous specification of the Markdown syntax, with BSD-licensed reference implementations in C (cmark) and JavaScript (commonmark.js). The spec repository contains the specification itself plus conformance test tooling with 500+ embedded examples for validating Markdown implementations.

## Use cases
- validate a markdown parser against the commonmark spec
- unambiguous markdown syntax specification
- test my markdown implementation with standard test suite
- convert markdown to html consistently across platforms
- extract spec test cases as json for my own parser
- resolve markdown rendering differences between implementations

## When to choose
- you are building or testing a Markdown parser and need a precise spec and conformance tests
- you need consistent, well-defined Markdown rendering behavior across systems
- you want a battle-tested reference implementation in C or JavaScript

## When to avoid
- you need Markdown extensions like tables or footnotes not covered by the core spec
- you just want a quick Markdown library without caring about strict spec conformance

## Facets
- artifact type: learning-resource
- maturity: stable
- function: parser, testing, documentation, markdown
- domain: documentation, parsers, web-development, developer-tools
- platform: cross-platform, cli, browser
- tags: markdown-spec, conformance-tests, reference-implementation, specification, nodejs

## Member repositories
- commonmark/cmark (main) score 77
- commonmark/commonmark-spec (docs) score 58
- commonmark/commonmark-java (sdk) score 93
- commonmark/commonmark.js (sdk) score 65

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:06.390067+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 2026-08-29T18:02:01.179119+00:00, confidence not recorded.
  - readme: https://github.com/commonmark/cmark (fetched 2026-08-28T04:06:06.390067+00:00, sha e9efb5161c90)
  - homepage: http://commonmark.org (fetched 2026-08-29T08:56:47.419185+00:00, sha a99eefad6c57)
- Data as of 2026-08-30T08:39:29.467469+00:00.