Accessibility testing tools and WCAG checkers compared

There are many good accessibility testing tools, and most of them are free. They differ less in what they find than in where they run (a browser extension, the command line, a cloud service), which rules engine they use and who reads the result: a developer, a QA team or a business owner. This page compares the tools people look for most, with facts taken from their official pages, and explains where Pandus fits.

Every tool on this page is an automated tester. None of them can confirm that a site meets WCAG; they find part of the problems. Our own checks are an automated check, not a full audit, and not legal advice.

Comparison table

Prices and features change; check each vendor's page before you decide.

WAVE

WAVE is a suite of evaluation tools by WebAIM at Utah State University. You enter a URL on the website or use the extensions for Chrome, Firefox and Edge. The extension runs entirely in your browser, so it also works on pages behind a login, local files and dynamic pages. Results appear as icons on the page and in a sidebar with errors, contrast errors and alerts for manual review. For many pages there is a subscription API and a stand-alone engine. It is a popular choice for learning, because it shows the problems where they are.

Lighthouse

Lighthouse is Google's open-source tool for page quality. Run it from the Lighthouse tab in Chrome DevTools, from the command line, or online through PageSpeed Insights. Its accessibility score is a weighted average of pass-or-fail audits based on axe rules; manual checks do not affect the score. That is useful as a quick signal, but a score of 100 covers only the automated audits — it does not mean the page meets WCAG.

axe DevTools and axe-core

axe-core is the open-source rules engine by Deque Systems that many tools build on, Pandus included. axe DevTools is Deque's product line around it: a browser extension with a free version, paid Pro features such as guided tests, a linter for VS Code and integrations for automated tests in CI.

Accessibility Insights for Web

Accessibility Insights is Microsoft's open-source tool set. The web extension for Chrome and Edge offers FastPass, which finds common high-impact issues in a few minutes, and an Assessment that walks people with HTML skills through the WCAG 2.1 AA criteria, including manual steps. There are also versions for Windows applications.

IBM Equal Access Accessibility Checker

IBM's Equal Access toolkit is open source under Apache-2.0. The checker integrates into the developer tools of Chrome, Firefox and Edge, and the accessibility-checker npm package runs the same rules in CI with Selenium, Puppeteer or Playwright. It uses IBM's own rule engine, with rule sets for WCAG 2.2, 2.1 and 2.0, so it is a good second opinion next to an axe-based tool.

Pa11y

Pa11y is a family of free, open-source command-line tools. Pa11y tests one page; Pa11y CI goes through a list of URLs and is made for pipelines. It can run HTML_CodeSniffer, the default, or axe-core.

BrowserStack Accessibility Testing

BrowserStack Accessibility Testing is a commercial service with its own Spectra rule engine, a browser extension for Chrome and Edge, a website scanner and CI integration. According to BrowserStack, its free plan includes unlimited on-demand website scans covering up to five unique pages. It fits teams that already use BrowserStack for cross-browser testing.

Where Pandus fits

Pandus uses the same open axe-core engine as Lighthouse and axe DevTools. The difference is what happens around the test:

• Every page, every week. A plan crawls the whole site on a schedule and shows what is new, what was fixed and the trend.
• Reports for business owners. Each finding comes with a plain-language rule card: what it means for customers, how to fix it on Shopify, WooCommerce, PrestaShop or Shoptet.
• Seven languages. Results and reports in English, Ukrainian, German, Polish, Czech, Romanian and Russian.
• EN 301 549 mapping. Every rule links to its WCAG criterion and its clause in EN 301 549 V3.2.1 and V4.1.1, the European standard behind the European Accessibility Act.
• White-label for agencies. Reports under the agency's brand, see Pandus for agencies.
• Free tools. The WCAG checker for one page, the contrast checker, the browser extension for pages behind a login and the WordPress plugin.

If you are a developer debugging one component, a DevTools extension is the faster choice. If you need to know every week whether a client's shop got worse, and explain it to someone who is not a developer, that is what Pandus is built for.

How to combine tools

1. During development: an axe-based extension or linter, plus a second engine (WAVE or IBM) for unclear cases.
2. In CI: Pa11y CI, the IBM npm package or axe-core in your end-to-end tests.
3. After launch: weekly monitoring of the whole site and reports for the owner.
4. Always: manual tests with a keyboard, zoom and a screen reader — see how to test WCAG. For a statement of conformance, hire an accessibility audit.

Frequently asked questions

What is the best WCAG checker?

It depends on the job. Browser extensions such as WAVE, axe DevTools, Accessibility Insights or IBM Equal Access suit developers checking one page; Lighthouse gives a quick score; Pa11y and the IBM npm package fit CI pipelines; monitoring services such as Pandus check whole sites every week and report to owners.

Which accessibility testing tools are free?

WAVE online and its extensions, Lighthouse, the free axe DevTools extension, axe-core, Accessibility Insights, IBM Equal Access Accessibility Checker and Pa11y can be used without paying. BrowserStack has a free plan with limits; Pandus checks one page for free.

Do WAVE, Lighthouse and axe DevTools give the same results?

Not exactly. Lighthouse, axe DevTools and Accessibility Insights use the axe-core engine, so their automated results overlap; WAVE, IBM Equal Access and Pa11y by default use their own rules. Running two engines can catch a few more issues.

Can any tool confirm WCAG compliance?

No. Every automated tool tests only part of the WCAG success criteria. A clean result is a good sign, not a confirmation; keyboard, zoom and screen reader tests by a person are still needed.

Where does Pandus fit?

Pandus runs axe-core on every page of a site each week, maps findings to WCAG and EN 301 549, and turns them into reports for business owners in seven languages, with white-label for agencies. It is an automated check, not a full audit.

Sources

• WebAIM, WAVE: https://wave.webaim.org/ and https://wave.webaim.org/extension/
• Chrome for Developers, Lighthouse overview: https://developer.chrome.com/docs/lighthouse/overview
• Chrome for Developers, Lighthouse accessibility scoring: https://developer.chrome.com/docs/lighthouse/accessibility/scoring
• Deque, axe DevTools: https://www.deque.com/axe/devtools/
• Microsoft, Accessibility Insights: https://accessibilityinsights.io/ and https://github.com/microsoft/accessibility-insights-web
• IBM, Equal Access toolkit: https://github.com/IBMa/equal-access
• Pa11y: https://pa11y.org/ and https://github.com/pa11y/pa11y
• BrowserStack, Accessibility Testing: https://www.browserstack.com/accessibility-testing and https://www.browserstack.com/accessibility-testing/free-accessibility-testing-tools