# segmentio/myth

A CSS preprocessor that acts like a polyfill for future versions of the spec.

Repository: https://github.com/segmentio/myth
Canonical: https://ross.abutalabs.com/products/myth
Language: JavaScript
License Family: other
Archived: true
Last push: 2023-04-09T21:26:19+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 4643, "days_push": 1242, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, archived, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 4287, forks 125 (observed 2026-08-28T04:08:41.328578+00:00)

## What it is
Myth is a CSS preprocessor built on Rework that lets you write pure, spec-compliant CSS with future syntax (variables, custom media queries, color functions) and compiles it to browser-compatible CSS today. It works both as a CLI and as a JavaScript API, and can re-process existing CSS from other tools.

## Use cases
- compile future CSS syntax to browser-compatible CSS today
- use CSS variables and custom media queries before browsers support them
- autoprefix and add vendor fallbacks to plain CSS
- re-process CSS output from Sass or Less without rewriting it
- write pure CSS while getting preprocessor-like features

## When to choose
- you want to write spec-compliant CSS that stays future-proof
- you need a lightweight CSS transformer with a simple CLI or JS API
- you want to add browser support to existing CSS without changing syntax

## When to avoid
- you need a full-featured preprocessor with mixins, nesting, and imports like Sass
- you need actively maintained tooling - the project has seen little activity and PostCSS is the modern standard
- you need runtime CSS calculations or complex build integrations

## Facets
- artifact type: library
- maturity: maintenance
- function: css-framework, build-tool, cli
- domain: web-development, frontend, web-design, developer-tools
- platform: cli, cross-platform
- tags: css-preprocessor, postprocessor, css-polyfill, rework, autoprefixing, css-variables, custom-media-queries, nodejs

## Member repositories
- segmentio/myth (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:08:41.328578+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 2026-08-29T18:21:56.300715+00:00, confidence not recorded.
  - readme: https://github.com/segmentio/myth (fetched 2026-08-28T04:08:41.328578+00:00, sha 96578e9df5e1)
  - registry_npm: https://registry.npmjs.org/myth (fetched 2026-08-29T09:11:28.425185+00:00, sha 6ba6cd0a04b0)
- Data as of 2026-08-30T08:39:29.467469+00:00.