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Testing for accessibility

Testing your service is an important step in meeting the Web Content Accessibility Guidelines (WCAG 2.1).

Test during development and check for accessibility issues regularly once it’s gone live.

Automated testing

Automated testing tools are a useful way of checking to see if your service is accessible. They are quick to run, provide instant feedback and can be used across lots of pages.

There are different automated testing tools available like Siteimprove, aXe and Wave. Some are free to use and can be accessed online.

Automated tools only pick up around 30% of accessibility issues, so it’s important to use manual testing to identify issues that have been missed.

Manual testing

Manual testing finds accessibility issues that automated testing has missed.

These include:

  • keyboard-only navigation
  • link text that isn’t descriptive (for example, ‘click here’ links)
  • lack of colour contrast
  • missing alt text
  • online forms that aren’t marked up correctly

You can use the handy accessibility checklist from 18F to complete a manual test for your service.

Accessibility checking tools

Colour contrast

You can check the accessibility of the colour contrast, using this free tool from WebAim. You will need to have the Hexadecimal colour codes handy.

You can also check colour contrast that includes transparency, using this free tool by Joe Dolson. You will need to have either of the following colour codes handy:

  • Hexadecimal
  • Red, Blue, Green (RGB)
  • Hue, Saturation and Luminance (HSL)

Free assistive technology tools

The Government Digital Service has a useful blog post with some recommendations for free assistive technology checkers.

PDF checker

The European Internet Inclusion Initiative has an online PDF checker, so you can check how accessible your PDF is.

Reading age

GOV.UK recommends writing for a reading age of 9. An assessment of reading age can be given by pasting an example of your content into the Readability Formulas website.