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WebAIM

Contrast checker with a JSON API, the WCAG 2 checklist, WAVE, and the Million report

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Aboutwebaim.org

WebAIM (Web Accessibility In Mind) is a non-profit centre at Utah State University and the de facto reference desk of web accessibility. It publishes the WCAG 2 and Section 508 checklists, an article library organised into five topic groups (the user's perspective; HTML, ARIA and CSS; documents and media; evaluation, testing and tools; standards and laws), cheat sheets, and the annual WebAIM Million report that automatically audits the top million home pages. Its tools matter most to an agent: the Color Contrast Checker and Link Contrast Checker both return JSON when you append `&api` to a query string, and the WAVE evaluation engine is available as a credit-based REST API and as browser extensions. Everything editorial is free; training, consulting, and WAVE API credits are paid.

For an agent

This is the one accessibility site in the index you can call rather than read: GET `https://webaim.org/resources/contrastchecker/?fcolor=RRGGBB&bcolor=RRGGBB&api` returns `{"ratio","AA","AALarge","AAA","AAALarge"}` with no key and no account, so use it to verify a generated palette instead of trusting your own maths. The link contrast checker takes an extra `lcolor` and reports link-to-text, link-to-background, and text-to-background separately — reach for it whenever you tint links inside body copy. Full-page auditing needs the paid WAVE API with a key, so do not plan an automated crawl around it; use the free contrast endpoints for colour and The A11Y Project's checklist for everything structural.

Why it is here. Twenty-five years of institutional authority plus a free, keyless JSON endpoint makes WebAIM uniquely useful to an automated workflow. The WebAIM Million is also the only longitudinal dataset on how accessible the real web actually is.

Install command, framework, licence and component list.
Notable for
  • free keyless JSON contrast API via &api
  • link contrast checker with three ratios
  • WCAG 2 and Section 508 checklists
  • WebAIM Million annual dataset
  • Utah State University non-profit
Provenance

Verified 2026-08-16. HTTP 200. https://webaim.org, https://webaim.org/resources/, https://webaim.org/articles/, https://wave.webaim.org/api/ (pricing table read), live calls to https://webaim.org/resources/contrastchecker/?...&api and https://webaim.org/resources/linkcontrastchecker/?...&api which both returned JSON

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