5 Open Source Accessibility Testing Tools – Pros and Cons

In my previous article, we’ve discussed the importance of accessibility testing. Accessibility testing is a relatively extensive field, thus selecting the best tool to validate accessibility testing is not easy. Many times we end up choosing multiple tools, since accessibility testing can not always be completed by using just one tool but rather with a combination of tools. There is no right or wrong choice, and it all depends on our needs.

Let’s review the pros and cons of the commonly used open source accessibility testing tools:

1. NVDA (NonVisual Desktop Access)
2. WAVE 
3. Colour Contrast Analyser
4. Axe
5. Pa11y

Pros and Cons of Open Source Accessibility Testing Tools

1. NVDA (NonVisual Desktop Access)

NVDA is a free screen reader that enables blind and visually impaired people to use a computer. This tool reads the text on the computer and thus helps the users. For accessibility testing, NVDA is used as one of the manual ways of testing to ensure that the website is made accessible for the blind and visually impaired.

Pros

• Simple to install and use.
• NVDA can convert text into braille (if the user has a braille display).
• Available in multiple languages.

Cons

• Only works with Windows (Not compatible with other OS types).
• Earlier versions had issues with Excel crash/chrome crash while using it, but it is reported that those issues got fixed in the latest release.
• Does not work with mobiles/tablets.

 

2. WAVE 

WAVE is a free web accessibility evaluation tool to determine web accessibility issues of the web via online sessions or by using browser plugins (Chrome and Firefox).

Pros

• Highlights the accessibility issues on the page itself. This gives a clear understanding of the issue, easier to locate the element (in which issue is marked) and get it fixed.
• Gives references for each issue, so that you can understand the root cause of the issue and make appropriate changes.
• Easy to use.
• No platform dependency.

Cons

• WAVE injects icons to the website when it scans the page. That often breaks the page layout.
• Current support is only for Chrome and Firefox.

 

3. Colour Contrast Analyser

Colour Contrast Analyser is a free software that helps to determine the accuracy or clarity of the text and the contrast of visual elements.

Pros

• The contrast ratio helps determine whether or not the contrast between two colours can be read by people with colour blindness or other visual impairments.
• Provides multiple ways to set colours such as raw text colours (any valid CSS format), RGB sliders, colour picker (Windows and macOS only).
• Provides support for alpha transparency on foreground colours.
• It has a colour blindness simulator which is very effective to know how the application will be accessible for colour blind users.
• No installation is required, running exe will do the job.

Cons

• Current support is for Desktop only.

 

4. Axe

Axe is a free accessibility tool kit from Deque Systems.

Pros

• APIs available for Android, Web (browser extensions) and Windows.
• Supports multiple browsers (Microsoft Edge v40 and above, Google Chrome v42 and above, Mozilla Firefox v38 and above, Apple Safari v7 and above, Internet Explorer v9, 10, 11).
• Ready to plug in integrations are available. So, for any automation framework it gives seamless integration feasibility.
• Selenium WebDriver integration is available. Hence end to end testing or multi-page testing is possible with Axe.
• Provides links to the rules where it failed.
• Axe gives an option to review issues. The issues under review are not really violations but they can be accessibility issues one should consider (maybe in the future).
• Axe generates hints to fix the violations.

Cons

• Axe can not be used to test iOS applications. 
• There is no results dashboard available

 

5. Pa11y

Pa11y is a command-line tool used to find accessibility issues in web pages.

Pros

• Supports web accessibility testing through headless mode. It internally uses headless chrome to evaluate WCAG rules.
• Provides a result dashboard interface to view the results.
• Generates hints to fix the violations.
• Easy to integrate with JavaScript frameworks.
• Can be integrated with CI tools such as Jenkins.

Cons

• Does not support mobile accessibility testing.
• Selenium integration is not possible.
• Multipage testing where session management is involved is a challenge.

What are your preferred accessibility testing tools? Share in the comments below! 🧐🙌