squizlabs/HTML_CodeSniffer

HTML_CodeSniffer is a client-side JavaScript application that checks a HTML document or source code, and detects violations of a defined coding standard. Comes with standards that cover the three conformance levels of the W3C's Web Content Accessibility Guidelines (WCAG) 2.0 and the U.S. Section 508 legislation. observed · 2026-08-28

github.com/squizlabs/HTML_CodeSniffer · homepage · JavaScript · BSD-3-Clause (permissive) observed · 2026-08-28

Health v2 · maintenance only

23/100

Activity 0
Release rhythm 8
Longevity 100

How is this computed?

round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10) — computed 2026-09-03. Adoption (stars, forks) is never an input.

gap_med: n/a
age_days: 5431
days_rel: n/a
days_push: 969
n_releases_24m: 0

Full methodology

Adoption not part of the score

1146 stars · 253 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

HTML_CodeSniffer is a client-side JavaScript library that checks HTML documents or source code for violations of defined coding and accessibility standards, including WCAG 2.1 (Levels A, AA, AAA) and U.S. Section 508. It can be called from JavaScript, run via a bookmarklet auditor, used as an npm module, or executed on the command line with a headless browser.

Use cases

audit a web page for WCAG 2.1 accessibility violations
check HTML source code against Section 508 standards
run automated accessibility checks in a headless browser from the command line
enforce custom HTML coding standards across a website with custom sniffs
quickly inspect any page's accessibility issues with a bookmarklet
integrate HTML accessibility linting into a Node.js build pipeline

When to choose

you need client-side, server-free HTML accessibility auditing
you need WCAG 2.1 or Section 508 conformance checks out of the box
you want a bookmarklet for quick manual audits of live pages
you need to define custom HTML coding standards via sniffs

When to avoid

you need full-page automated testing with modern tooling like axe-core or Lighthouse
you need server-side rendering checks or non-HTML document formats
you require actively developed tooling with frequent updates

Facets

library · maturity maintenance

testing accessibility linter browser-extension web-development accessibility developer-tools testing browser cli wcag section-508 html-auditing bookmarklet a11y-testing nodejs javascript

3 sources

readme: https://github.com/squizlabs/HTML_CodeSniffer · fetched 2026-08-28 · 9799fb6a35ed
homepage: https://squizlabs.github.io/HTML_CodeSniffer/ · fetched 2026-08-29 · ab76c1eed1df
registry_npm: https://registry.npmjs.org/html_codesniffer · fetched 2026-08-29 · 6382a226c376

Member repositories

Repository	Role	Health v2
squizlabs/HTML_CodeSniffer	main	23

For agents

markdown · JSON · MCP: product_card(name="squizlabs/HTML_CodeSniffer")

Data as of 2026-08-30T08:39:29.467469+00:00 · Report a problem