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Accessible Technology

Tools

This page provides an annotated list of free tools for checking accessibility of digital resources.

Tools

Accessibility checkers & browser extensions

The following tools are listed alphabetically.

  • Accessibility Bookmarklets
    This suite of bookmarklets can be used in any browser and work by visually highlighting specific accessibility features within a web page, including ARIA landmarks, headings, lists, and accessibility-related features of images and forms.
  • Accessibility Insights
    This robust accessibility checker and educational tool from Microsoft is available as an extension for Chrome or Edge, or as downloadable software for checking Windows applications.
  • AInspector WCAG Firefox Extension
    This extension was developed at the University of Illinois.
  • axe
    This accessibility testing toolkit from Deque is available as an API that can be integrated into automated testing processes for web development. Android Accessibility is also available as well the axe Chrome Extension.
  • WAVE
    Developed by WebAIM, this online tool evaluates the accessibility of a web page and shows results using icons and indicators, embedded onto the original page. It is available as a standalone website, or as the WAVE browser extension for both Chrome and Firefox.
  • Web Developer Extension for Firefox or Chrome.
    This highly useful toolbar from Chris Pederick is packed with features, including many that help check web pages for accessibility features.

Browsers’ Built-in accessibility tools

Many browsers have their own accessibility tools built into their developer tools. For more information, see the documentation for the tools available in your preferred browser.

Code validators

Having valid code is a first step toward web accessibility and cross-browser compatibility. The following tools should be used regularly for checking the validity of your code.

  • HTML Validator – from the W3C
  • CSS Validator – from the W3C
  • HTML Tidy – This is a software library that evaluates and cleans up HTML, automatically generating a reformatted (i.e., “tidied”) version. HTML Tidy is widely available, and is integrated into many web coding applications as documented on their website.
  • HTML Validator Browser Extensions – for Chrome and Firefox, based on HTML Tidy and OpenSG, includes accessibility checks that can be toggled on via the Options menu
  • WebVTT Validator – for validating timed text files to be used with HTML video, e.g., for captions, subtitles, chapters, and descriptions.

  • PDF Accessibility Checker (PAC) – free PDF Accessibility Checker that reviews requirements against both WCAG and PDF/UA success criteria and provides a detailed report. (platform: Windows only) 
  • axesCheck – free web-based PDF Accessibility Checker that provides a basic pass-fail report against WCAG and PDF/UA success criteria. 
  • Office 365 Accessibility Checker – resource from Microsoft for using the built-in accessibility checker in Word, PowerPoint, Excel, and other Office 365 products to create born accessible content. (platform: Windows 10, 11; macOS, Web) 
  • Adobe Acrobat Pro Accessibility Checker – resource from Acrobat for using the built-in accessibility features of Adobe Acrobat Pro to improve accessibility of PDF documents. (platform: Windows, macOS) 

Accessibility standards require a specific contrast ratio between foreground and background colors. There are several tools available for measuring whether particular color combinations meet these standards:

  • Colour Contrast Analyser – This downloadable software application, available in Windows and Mac versions, makes it easy to check foreground & background color combinations. Both versions include an eyedropper tool for easily grabbing a particular color from anywhere on the screen.
  • WCAG Contrast Checker for Firefox – This Firefox extension displays color contrast ratios in a sidebar, and flags the color combinations that fail WCAG contrast requirements at various levels.
  • WebAIM Color Contrast Checker – This handy online tool includes a feature to “lighten” or “darken” existing colors until you find a combination that meets WCAG contrast requirements. This functionality is also built into the WAVE Extension (see WAVE under “Third Party Accessibility Checkers & Browser Extensions”).
  • WCAG Color Contrast Checker – This web tool from seigemedia provides a simple interface for comparing colors.
  • UW Colors Contrast Table – A quick guide for selecting combinations of UW brand colors that meet accessibility requirements for contrast.

  • Image Accessibility Creator – resource from Arizona State University to help draft Alt Text and Long Description for images and complex graphics and charts.  
  • Math Detective – resource for generating draft alt text for images of math formulas. 

Screen readers are tools that are commonly used by individuals who are blind or low vision to read the content of desktop or mobile computing devices using a synthesized voice.

When testing web pages and other digital resources with screen readers or other assistive technologies (AT), it is important to be aware that no two AT products are alike. What seems to work perfectly in Product A may be inaccessible in Product B. Therefore, developers should resist the tendency to develop sites and applications that work with a particular AT product, and focus instead on developing sites that comply with standards.  Also, full-time AT users develop skills, strategies and workflows for using their tools over many years of experience. When using these same tools for testing accessibility, it is important to keep this limitation in mind.

The following are commonly used screen readers in various platforms.

  • NVDA – A free, open source screen reader for Windows.
  • JAWS (not free) – The most popular screen reader in Windows.
  • Narrator – Microsoft’s screen reader, built into Windows. This is a simple screen reader, minimally featured compared to NVDA and JAWS, and not commonly relied upon for daily use.
  • VoiceOver – Apple’s screen reader, built in to both Mac OS and iOS devices.

Each of these tools, and many other assistive technologies, are available for use in the Access Technology Center.

WebAIM publishes several relevant resources: