Understanding who your users are

These tools and resources can help you uncover problems in your services and websites. You should use these tools to understand what problems or barriers you may be introducing to your services.

During Discovery, you must understand the types of people who may be using your service. This includes users who have access needs, permanent or situational impairments and who may be using assisitive technologies.

Important: Tools and resources

Use this online service to estimate how many people using your website might be disabled. This will help you consider the types of people who may be using your service and who you should be testing with.

Colour tools

  • WebAIM color contrast checker compares two hex colors and tells you whether they meet WCAG AA and AAA contrast thresholds.
  • Snook’s color contrast analyzer lets you adjust RGB and HSV values and reports contrast compliance interactively.
  • Color Safe is a guide for choosing colors that meet WCAG contrast thresholds.
  • Contrast a toolbar app for Mac users to check contrast of anything on screen.
  • Color Contrast Analyzer is a desktop application for contrast checking that also simulates different forms of color impairment.
  • Toptal Colorblind Web Page Filter is webpage which simulates what websites look like to people with different types of color blindness.
  • Color Oracle is a desktop application for simulating color impairment on your entire screen.
  • Colorblind is another simulation tool similar to Daltonize, but with more options (protanopia, protanomaly, deuteranopia, deuteranomaly, tritanopia, tritanomaly, achromatopsia, and achromatomaly) in a single bookmarklet.
  • postcss-colorblind is a CSS build tool that modifies colors in your CSS to simulate four common impairment groups.


User profiles you can use to configure a device, which demonstrate common barriers users face when using services.

These should not be used as the only method to test your service works for users with access needs.

Browser tools

  • Accessibility Insights is a browser plugin for Chrome and Edge, Android and Windows applications for automated and guided manual testing.
  • Lighthouse is an accessibility and best practice tester, it's built in to Chrome and Edge browsers through the Inspect panel.
  • axe is a browser plugin to test accessibility for Chrome and Edge


To use bookmarkets, either, drag the link to your favourites bar or right click and add to bookmarks / favourites. You can then click on them in your bookmarks bar to run them against a page.

  • Headings highlights the headings on a page to allow you to check nesting and order
  • Disable CSS to test content is readable with styles disabled
  • Lists identifies lists on a page to check they are the correct type
  • ARIA identifies ARIA labelling on a page
  • Images identifies images on a page

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