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Six accessibility check cards: 4.5:1 WCAG AA contrast, headings, keyboard, image alternative text, PDF/UA and screen reader

Best accessibility testing tools for web applications

Clement Egger

Accessibility testing tools check a web page against rules such as the WCAG success criteria and report what they can detect. They catch some of the issues and leave the rest to human review, so they help you size the work before an audit.

Accessibility testing software ranges from browser extensions to command-line tools. These 11 accessibility testing tools cover everything from checking a single page to checking PDFs. Running them before an audit gives you an overview of the work required and helps you plan resources accordingly.

What accessibility testing tools can and cannot check

An automated accessibility testing tool applies a set of rules to a page and reports what it can detect, such as missing text alternatives, empty buttons or low color contrast. It cannot judge whether a text alternative is relevant or whether a page makes sense with a keyboard. For that, a person needs to test with the keyboard and a screen reader.

Even the engines built for automation say so: axe-core, the open source engine from Deque, marks a result as incomplete when it cannot be certain and manual review is needed. A good test combines both approaches.

Accessibility testing tools at a glance

ToolTypeLicense or costStandard or scopeGood for
WAVEBrowser extensions and APIExtensions, subscription APIAccessibility and WCAG errorsVisual check of a single page
axe DevToolsBrowser extension built on axe-coreaxe-core is open source (MPL 2.0)WCAG 2.0, 2.1 and 2.2Developers and automated tests
LighthouseAudit run in Chrome DevTools or the command lineSee publisherAccessibility audits weighted by impactA quick score and a list of issues
Accessibility Insights for WebBrowser extensionOpen sourceWCAG 2.1 AA assessmentGuided automated and manual checks
Pa11yCommand-line toolFree and open sourceAccessibility issues on pagesRunning checks across many pages
ARC ToolkitBrowser extensionFreeWCAG 2.1 A and AAOne page at a time, with contrast and tab order
HeadingsMapBrowser extensionSee publisherHeading structureChecking heading levels
Colour Contrast AnalyserDesktop applicationFreeWCAG 2.0, 2.1 and 2.2 contrastColor contrast
NVDAScreen reader for WindowsFreeManual testingTesting as a screen reader user
VoiceOverApple screen readerSee AppleManual testingTesting on Apple devices
PACWindows applicationFreePDF/UA and WCAGPDF accessibility

Web accessibility testing tools for websites and web applications

WAVE

WAVE, from WebAIM, is a suite of evaluation tools that helps authors make web content more accessible. Browser extensions for Chrome, Firefox and Edge test a page directly in the browser and point out accessibility and WCAG errors on the page itself. A subscription API and a stand-alone API with the testing engine exist for teams that want to build testing into their own infrastructure.

axe DevTools

axe DevTools is Deque's bundle of accessibility testing tools for websites and web apps, with a browser extension for Chrome, Firefox and Edge. Underneath, axe-core is the open source accessibility testing engine, released under the Mozilla Public License 2.0. Its rules cover WCAG 2.0, 2.1 and 2.2 at levels A, AA and AAA, plus a set of best practices. It is designed to run alongside existing functional tests.

Lighthouse

Lighthouse can be run in Chrome DevTools, from the command line or as a Node module. It has audits for performance, accessibility, SEO and more. Its accessibility score is a weighted average of accessibility audits. Each audit passes or fails. The weights come from axe impact assessments. Manual audits are not part of the score, so a high score does not replace a manual review.

Accessibility Insights for Web

Accessibility Insights for Web is an open source browser extension for Chrome and Microsoft Edge, from Microsoft. Its FastPass starts with the common, high-impact issues and is meant to take less than five minutes. The tool can then guide you through an assessment of WCAG 2.1 AA coverage.

Pa11y

Pa11y is a set of free and open source tools that help designers and developers make web pages more accessible. Its command-line interface loads web pages and highlights accessibility issues. pa11y-ci runs through a list of pages and is geared toward continuous integration.

ARC Toolkit

ARC Toolkit, from Vispero, is a free browser extension for Chrome and Firefox. It checks one web page at a time against the WCAG 2.1 Level A and AA guidelines. It also identifies color contrast problems and highlights tab order.

Screenshot of an accessibility audit tool in the browser: list of errors and alerts sorted by topic, such as contrast and keyboard navigation

HeadingsMap

A relevant hierarchy of headings is essential to the accessibility of a page. The HeadingsMap extension for Chrome and Firefox generates a document map of the page from its headings and HTML5 sections and shows the errors in the structure, such as incorrect heading levels.

Screenshot of a heading map tool for a web page: the tree of headings on the left and an online newspaper page on the right

Tools for color contrast, screen readers and PDF documents

Colour Contrast Analyser

The Colour Contrast Analyser, from Vispero, is a free application for Windows and macOS. It calculates contrast ratios against WCAG 2.0, 2.1 and 2.2 criteria. At level AA the thresholds are 4.5:1 for normal text and 3:1 for large text. It includes an eyedropper to pick colors from the screen and a color blindness simulator.

A computer screen displaying the message Contrast Failure next to a color contrast analyzer tool reporting a failure

NVDA

NVDA is a free screen reader for Windows 10 and later, made by NV Access. Browsing a page with it shows how a screen reader user hears the heading hierarchy, the text alternatives of images and the labels of interactive elements.

VoiceOver

VoiceOver is Apple's screen reader. Apple provides setup guides for iPhone, iPad and Mac, so you can test the same points as with NVDA on Apple devices.

PAC

PAC, the PDF Accessibility Checker, is a free Windows tool from the PDF/UA Foundation. It checks the accessibility of PDF files against PDF/UA and WCAG. It also offers a screen reader preview and a tag tree view.

Browser extension, plugin or widget: what is the difference?

These three terms name different tools. A browser extension is installed by the person who tests and flags issues on the page on screen. A plugin or module is installed in the CMS of a site or in a design tool. A widget is added to a site and gives its visitors display settings.

Several tools on this page come as browser extensions, including WAVE, axe DevTools, Accessibility Insights for Web, ARC Toolkit and HeadingsMap. Pa11y is a command-line tool.

What do the standards say? WCAG 2.2 states that conformance is for full web pages only. The WCAG-EM 2.0 evaluation methodology from the W3C sets out an evaluation in steps: define the scope, explore the site, select a representative sample of pages unless the whole site is evaluated, evaluate it and report the findings. Conformance is assessed on the pages themselves.

The plugin or extension you can install also depends on your CMS, whether it is traditional, headless or hybrid. The choice is made with the team that runs an enterprise CMS or a DXP platform as much as with the accessibility team.

Which standard to test against

Test against WCAG 2.2, the current W3C Recommendation since 5 October 2023. WCAG 2.0 and 2.1 remain Recommendations. The W3C advises using 2.2. WCAG 3.0 is still a working draft. Tool coverage varies: the axe-core rules cover WCAG 2.2, while ARC Toolkit and the Accessibility Insights assessment target WCAG 2.1. Check which version each accessibility testing tool tests.

In the European Union, Directive (EU) 2019/882, the European Accessibility Act, has applied since 28 June 2025 to certain services provided to consumers. In France, the national reference is the RGAA, currently in version 4.1.2 (updated on 18 April 2023), with a version 5 in preparation for the end of 2026.

Jahia accessibility resources

We have put together resources to help you answer questions about web accessibility and accessibility testing, depending on where you are in your journey:

FAQ

What are the best accessibility testing tools?
There is no single best tool, because each one covers a different need. WAVE gives a visual check of a page, axe DevTools and Pa11y fit developer workflows, Lighthouse and Accessibility Insights for Web give a quick first pass. A screen reader such as NVDA or VoiceOver covers what automated tools cannot judge.

How can I test a website's accessibility?
An accessibility test takes three passes. First, an automated check with an accessibility testing tool such as WAVE, axe DevTools or ARC Toolkit, which flags the issues a tool can detect. Second, a specialized tool for each type of issue, such as the Colour Contrast Analyser for contrast or PAC for PDF files. Third, a human pass with the keyboard and a screen reader.

Which accessibility testing tools are free and open source?
NVDA, ARC Toolkit, the Colour Contrast Analyser, PAC and Pa11y are free. axe-core, Accessibility Insights for Web and Pa11y are open source. WAVE offers browser extensions and a separate subscription API. For Lighthouse, HeadingsMap and VoiceOver, check the publisher's page. Terms change, so confirm them before you choose.

What is the difference between automated and manual accessibility testing?
Automated testing applies rules to a page and reports what a tool can detect, such as missing text alternatives or low contrast. Manual testing checks what rules cannot judge, such as keyboard use and the relevance of text alternatives. Engines such as axe-core flag the results they cannot decide on, which a person then reviews.

Which accessibility testing tool checks color contrast?
The Colour Contrast Analyser calculates contrast ratios against WCAG 2.0, 2.1 and 2.2 criteria on Windows and macOS. At level AA it expects 4.5:1 for normal text and 3:1 for large text. You can pick colors from the screen with an eyedropper or enter HEX, RGB, HSV or HSL values. A simulator shows how color blind users see the page.

Which standard should I test against?
Test against WCAG 2.2, the W3C Recommendation published on 5 October 2023. In the European Union the European Accessibility Act has applied since 28 June 2025 to certain services provided to consumers. In France the RGAA applies, currently in version 4.1.2, with a version 5 expected at the end of 2026.

Which browser extensions can test accessibility?
Several tools on this page come as browser extensions, including WAVE, axe DevTools, Accessibility Insights for Web, ARC Toolkit and HeadingsMap. Each one checks the page displayed in your browser. They detect part of the issues, so a person still reviews the rest, with the keyboard and a screen reader.

How do I run a website accessibility audit?
Follow the WCAG-EM 2.0 steps from the W3C: define the scope, explore the site, select a representative sample of pages or evaluate the whole site, then evaluate and report the findings. Tools from this page speed up the check of each page, while a person verifies what they cannot judge, such as keyboard use and the relevance of text alternatives.
Black and white portrait of Clément Egger

Clement Egger

Clément Egger, Senior Product Manager at Jahia, has in-depth expertise in defining product strategies and managing roadmaps for CMS and DAM solutions. He shares his knowledge of the market, and a keen eye for how organizations can develop innovative solutions and functionalities. 

https://www.linkedin.com/in/clementegger/

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