What Is Web Accessibility Testing, and How Do I Do It?

Posted on: May 8, 2024


Helen Halfpenny


With so much of our lives online now, website accessibility is not just a nice to have. It’s a legal requirement. But many websites are not even meeting the most basic accessibility criteria, meaning that millions of people are unable to navigate them properly, or at all! 

Web accessibility simply means ensuring that people with disabilities can access, understand and interact with all of the content on your site, no matter how they navigate the web. It’s complex, and often technical, but getting it right is vital. And with user experience (UX) and SEO being more closely-linked than ever, making your website accessible can have benefits for these areas too…

So, how do you make sure your website is accessible? Well, fortunately, the Internet (of course!) is here to help. In this article, we’ll look at the various ways that people with disabilities navigate the web, and how you can use accessibility testing tools to make sure your site works for everyone. We’ll also touch on the benefits for UX and SEO, and briefly cover the Web Content Accessibility Guidelines (WCAG).

So, let’s dig in…

Visually impaired working on computer with assistive technology; braille display and screen reader.

Who Is Web Accessibility For?

In a word: everyone! Literally everyone benefits from websites being accessible. In theory, it is aimed at people with disabilities that prevent them from using traditional means to browse the internet. This may mean they use a screen reader, alternative input device, keyboard navigation, or various other methods. 

The WHO estimates that an estimated 16% of the world’s population has some form of disability. These usually fall into the following areas:

  • Visual
  • Auditory
  • Mobility-related
  • Cognitive
  • Neurological

But, while accessibility primarily targets these users, as mentioned above, it has added bonuses for all users. By making your site accessible, understandable and easy to interact with, you are enhancing the user experience across the board, not just for users with disabilities. 

What’s more, Google prioritises websites that offer a good experience for their users, so fixing accessibility issues may also see you rewarded with a nice little (or big) rankings bump!

Understanding the WCAG

The Web Content Accessibility Guidelines (WCAG) are the internationally recognized standards for web accessibility. Developed by the World Wide Web Consortium (W3C), these guidelines provide a framework for creating accessible web content. WCAG is organized around four principles:

  • Perceivable - focusing on how a website appears to users. For example, can your text be read against the background or are there contrast issues? Or, are there text alternatives for non-text content? 
  • Operable - can users interact with all of your content, including radio buttons, menus, popups and forms?
  • Understandable - Can your users understand your content? Is it easy to read and process? Are there labels on form fields, and clear instructions provided where needed?
  • Robust - Can your website be navigated on different devices, including screen readers, older devices and older versions of web browsers?

Each of these 4 principles (also known as POUR principles), has guidelines and success criteria associated with it to help web developers and website owners ensure accessibility for all users.

WCAG Compliance

There are 3 levels of compliance within the WCAG: A, AA and AAA. From a legal perspective, in order to comply, websites must achieve level AA. This means, among other measures, providing alt text for images, making sure content is presented in a clear and logical manner, and ensuring that sites are compatible with various technologies including different browsers and assistive technologies. 

Accessibility, UX and SEO - Oh My!

Accessibility, user experience (UX) and SEO are now more closely intertwined than ever before. Google wants to deliver to users websites that provide excellent user experiences. That means fast load times, clear and easy-to-read content, descriptive headings, easy-to-use navigation and menus, mobile accessibility… the list goes on. 

Accessible websites deliver all this and more. They do not only cater to users with disabilities, but provide a better user experience overall. And the benefits are easy to see:

  • Better engagement - visitors are more likely to stick around and buy from you , not to mention come back in the future.
  • Broader reach - if your site’s not accessible, you’re excluding a whole spectrum of potential customers
  • Brand reputation - demonstrating a commitment to accessibility can help build trust and goodwill among users.

Accessibility and SEO

Web accessibility can also help when it comes to search engine optimization (SEO). Search engines like Google want to send their users to websites that offer a good user experience, but more than that, accessibility can help your content rank better. Here’s how accessibility can benefit SEO:

An example of good and bad alt text where the image is a donut with purple and pink sprinkles
  • Faster loading times - page speed is a ranking factor, and accessibility improvements often help pages load faster
  • Better content structure - accessibility means organising content in a clear and ordered way, with relevant headings. This can also make it easier for search engines to understand.
  • Reduced bounce rates - if a user lands on your site and can’t do what they need to do, they’ll bounce, which could indicate to search engines that your content might not be relevant to users. 
  • Mobile-friendliness - Google looks at the mobile version of a website for indexing, so you need to make sure your site works on mobile. Accessibility practices often benefit mobile users too - for example, having the ability to pinch and zoom, or having a responsive website that scales to different devices.
  • Alt text, transcripts etc - providing text descriptions of images and transcripts of videos and audio recordings can provide relevant, additional text content for your website, and also help your media get indexed in video and image search.

How Do Users with Disabilities Navigate the Web?

Accessibility is not just about making sure that your visitors can access your content; they also need to be able to navigate through it, understand it and interact with it effectively, no matter what method they’re using. 

Here are some of the navigation methods that visitors may use:

  • Keyboard navigation - some users may not be able to use a mouse or track pad, and rely on keyboard navigation instead. This means that all content and interactive elements must be accessible through tabbing and keyboard shortcuts. Users must be able to fill out and submit forms, close any popups that appear and access tabbed or accordion content.
  • Screen readers - users with visual impairments may use screen readers to navigate the web. For these users, your content must be delivered in a clear and logical way, using appropriate headings and semantic HTML elements, plus ALT text for images.
  • Voice commands - some users may rely on voice commands to navigate websites. 
  • Alternative inputs - these may include joysticks, sip-and-puff devices and eye-gaze technology.
An elderly internet user, using a laptop and making notes with paper and pen

Understanding these different methods of navigating the web and ensuring your site is accessible for them ensures you will create a fully inclusive user experience.

The Importance of Accessibility Testing

It’s clear there are a lot of variables involved in web accessibility and creating an inclusive user experience for all, so getting it right can be tricky. You have to balance legal compliance, accessibility, user experience, great design and technical SEO, and sometimes they don’t align as they should!

This is why testing your website against the various different accessibility criteria, and using different methods to navigate your customer journey is vital. There are plenty of automated testing tools available, but if you want to be compliant and inclusive (and you do!), you need to look at your website through many different lenses and do manual testing as well.

Using Web Accessibility Testing Tools

Fortunately, as mentioned above, there are plenty of tools easily available to help you test your website’s accessibility. Here are just a few:

  • Axe Dev Tools - this is a really handy testing tool that scans your web pages and identifies issues based on the WCAG web accessibility guidelines. To use this tool, download the plugin from [link] and navigate to your chosen page. You can then run a scan and it will highlight all the accessibility issues found, along with suggestions for fixes as per the WCAG criteria. You can scan pages for free, but if you want to save results or get more detailed audits, you’ll need to get a paid plan.
  • Lighthouse - this is a great tool from Google. It offers dozens of suggestions and solutions for improving page performance, from speed issues to mobile-usability, to accessibility. Just run a page through it and see what pops up!
  • Microsoft Accessibility Insights - Free Microsoft tools that use Deque’s Axe technology. There’s a browser plugin for checking web pages, and you can easily run quick checks, or more in-depth assessments.
  • Site crawlers, such as Sitebulb - Sitebulb can carry out accessibility checks as part of a crawl. You won’t find much information outside of what Axe Dev Tools or Lighthouse offer, but it’s handy for seeing how widespread accessibility issues are on your site and for seeing which pages are affected. 

Aside from these tools, there are other ways you can check your website’s accessibility:

  • Ask users - ask users with disabilities to use their preferred methods to navigate your website and get first-hand feedback about any issues they may face.
  • Screen readers - Download a screen reader and try to navigate through your website or customer journey with it. This may seem overwhelming, but it’s vital. Some popular screen readers include NVDA, JAWS and VoiceOver.
  • Keyboard navigation - Test the customer journey on your website using keyboard shortcuts and tabbing - at a minimum, use your arrow keys and tab key. Consider things like radio buttons, modals and pop-ups, forms and keyboard focus.
  • Browser plugins - You can download browser plugins that simulate various scenarios, such as colour blindness, to see how users with these disabilities may perceive your site.
  • Zooming/magnifying - some users with visual impairments may need to resize your content in order to read it. Use your browser’s built-in zoom tool to do this yourself and make sure your content still displays correctly and is readable.
  • Responsive Viewer - this is a handy little plugin which simulates your site loading on various different device sizes. It’s great for getting an idea of what your pages look like and where content might not be displayed or layouts might be broken.
  • Checklists - there are lots of accessibility checklists available online, this one from gov.uk covers the most common issues you’re likely to encounter and the respective WCAG criteria that apply. 

In conclusion, website accessibility is not only a legal requirement, but is also vital to creating an inclusive and user-friendly experience on your website. By considering the many ways - and many types of assistive technology - that are used to navigate the web, employing the above testing tools, and recognising the close connection between accessibility, UX and SEO, you’ll reap the benefits of happy visitors and happy search engines too!


If web accessibility all seems a bit daunting, why not get in touch with us? We regularly carry out accessibility and UX audits on behalf of our clients, and, as a full-service digital agency, we not only highlight the issues, but our web development team can help fix them for you too!

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Helen Halfpenny

SEO Strategist

I’ve been working in digital marketing for over a decade now, both agency-side and in-house. Over the years, I’ve managed the SEO, PPC, email and affiliate campaigns for a major UK retailer, and the SEO, CRO and ongoing website updates for a well-known ISP. Agency side, I have run successful SEO and email campaigns for large high-street retailers, as well as for smaller local businesses. It’s fair to say that I have a broad range of experience in marketing, but SEO is where my heart truly lies!

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