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Screen reader testing

When it comes to web accessibility, people with sight loss using screen readers to complete online tasks is often the first thought that springs to mind. But that’s where the knowledge gap kicks in. How do screen readers actually work? Are they all the same? And why should you conduct screen reader testing on your website? Read on to learn how to perform effective screen reader testing of your web content and provide a more accessible website experience to all your site visitors.

What are screen readers?

Screen readers are a specialist text-to-speech software that can be used by people with little to no vision to access website content, generally on a computer or mobile device. They are designed to run on the most popular operating systems, like Windows, iOS and Android. The content they can decipher includes emails, web pages and other documents.

This is typically achieved by the screen reader ‘announcing’ the site’s content (headings, text, links, images and so on) in an artificial voice – also known as a speech synthesizer – via the user’s device’s sound card. Some screen reader technologies also allow their users to access web content via a refreshable braille display, which is particularly useful for deaf-blind people. Screen readers can be used to access web content at home, at work or in educational environments.

As well as providing a speech output, some screen reader technologies allow the magnification of web content and altering the appearance of a web page, for example, by increasing the contrasts or inverting colors. These capabilities are helpful for users who have limited vision or color blindness.

As many users with sight loss cannot accurately navigate web content with a mouse, they will typically control their screen reader using keyboard commands or by making gestures on a trackpad or touchscreen. This enables them to use a computer to perform the same tasks as a sighted user. The exact features available and the mechanics of how this process works depend on the specific screen reader being used – not all screen readers are the same. As with most technologies, there are a number of competing brands and styles featuring different capabilities. They can be either paid-for or free. Some come built-in to the user’s device, such as the software that runs on the Android or iOS platforms.

Popular screen reader software includes:


  • NVDA
  • Windows Narrator
  • VoiceOver (macOS/iOS)
  • Orca (Linux)


  • JAWS
  • Dolphin
  • Window-Eyes
  • System Access

People with vision loss might even use more than one screen reader, for example, if they use both Windows and Mac devices. Most screen readers can be customiszd to meet the needs of the user, for example, by changing the speed of the screen reader’s speech or altering the level of punctuation that is spoken. They are also available in multiple languages.

Who uses screen readers? 

Screen readers are most commonly used by people with sight loss. This can be someone who is blind and cannot see what is on a screen or someone who is partially sighted, meaning they cannot reliably discern all types of content on a screen. Some people with cognitive and learning disabilities also benefit from using a screen reader so they can simultaneously hear and see a web page’s content.

What all screen readers have in common is that they enable their user to independently use a computer or mobile device to perform everyday online tasks – without needing a screen output. That includes browsing the web, writing emails, making online purchases and accessing multimedia content.

As screen reader users are likely to make up most of the people who benefit from you having an accessible website, it’s a very good idea to gain a first-hand understanding of the challenges they face when using their screen reader by incorporating screen reader testing into your web accessibility auditing and monitoring.

How do visually impaired users experience websites? 

Screen reader users will experience your content differently to users who don’t rely on assistive technology. Here are some of the key differences between how a sighted user and someone using a screen reader perceives your content.

Keyboard navigation: Users with sight loss often rely on keyboard navigation rather than the standard combination of visual cues and a mouse to access web content. Not providing keyboard access on your website presents a major roadblock for them.

Scanning and skipping: It’s common for a screen reader user to use keyboard commands to skip between different sections of a web page, rather than listening to the entirety of a page being read out. That means jumping between sections quickly so they can locate the information that is most pertinent to them. They can only do this effectively if a website has been designed with screen reader usage in mind, such as using proper HTML formatting.

Images: As users with vision loss might struggle to accurately discern an image, they generally rely on accurate and descriptive alternative text to understand their meaning. Missing or improper alternative text poses an obstacle to their comprehension.

Design: While sighted users tend to use visual design cues to understand and navigate your content, screen reader users perceive your content in a linear, text-based fashion. Design elements like color and positioning, for example, carousels and pop-ups, hold less meaning for them and can even be distracting when using a screen reader.

Links: Many screen reader users ‘tab’ from link to link to find content quickly on a page. This is much easier for them when the links are descriptive, rather than using ambiguous link anchor text like ‘click here’ and ‘learn more’.

Why is screen reader testing important? 

Accessibility oversights like not adding alternative text to an image or omitting headings can make the difference between a visitor using a screen reader accessing your content effectively or dismissing your site as unusable and unsuitable for them.

While automated testing can detect many accessibility errors on your website, for a fully comprehensive audit and to ensure everything is working as expected after you’ve carried out accessibility remediation, you must also perform manual accessibility testing with a screen reader. This is not a step you should skip.

Screen reader testing helps you gain hands-on experience with the most common obstacles screen reader users come across on websites. You are quite literally putting yourself in their shoes when it comes to navigating your website. Drawing on these insights, you can design content that more accurately meets this audience’s needs and increases your potential market share, as well as establishing your reputation as an inclusive organization.

With almost two million people living with a form of sight loss in the UK, you risk underservicing or even losing this demographic’s business to more accessible competitors if your website isn’t set up to work effectively with screen readers. Coupled with the UK’s ageing population, the number of people with sight loss is also expected to increase in the future – by 2030, an estimated 2.7 million people will live with some type of visual disability. These numbers should alert you to the growing importance of designing a website that is compatible with screen readers.

On top of this, you may be breaking the law if your website does not mean the accessibility requirements laid out in legislation like the EU Web Accessibility Directive, The Public Sector Bodies (Websites and Mobile Applications) Accessibility Regulations and The Equality Act 2010. These laws refer to the Web Content Accessibility Guidelines (WCAG), which include several requirements that are applicable to screen reader usage, such as setting standards for alternative text.

And if you don’t think your website visitors with screen readers are part of your audience – perhaps because you’ve never seen them represented in your website traffic – think again. Analytics software like Google Analytics and Siteimprove Analytics do not track assistive technologies like screen readers.

Next up, it’s time to learn how to perform a screen reader accessibility test. 

How to perform screen reader testing

Before you dive into screen reader testing, it’s important to note that testing with a screen reader alone does not guarantee that your site is fully accessible. A combination of automated and manual testing – with and without screen readers - is also required.

Using a screen reader to test the accessibility of your content sounds straightforward enough, but jumping straight into screen reader testing without some basic knowledge of assistive technologies can actually be counterproductive. Either designate these checks to someone who is familiar with screen readers or ensure you’re up to speed with at least the basics before you begin. Getting acquainted with some of the most common keyboard shortcut commands will also be beneficial.

Once you’ve got the basics covered, you can begin your testing. So, where should you begin? There are some specific areas that it makes sense to prioritise as they are where screen reader accessibility errors tend to crop up most frequently. These problem areas are:

  • HTML mark-up: Does your website use semantic HTML mark-up for elements like headings, paragraphs, lists, tables and forms?
  • Alternative text: Does your website use descriptive alternative text for images, icons and non-text content?
  • Keyboard compatibility: Is your site navigable using keyboard-only commands?
  • Visually-led content: Is your web content understandable without visual cues? For example, is link text descriptive? Do instructions require a visual cue, e.g. click on the red box to download?
  • Dynamic content: With content becoming increasingly complex and dynamic, moving and changing elements on a screen can be an obstacle to comprehension. Disabling automatic carousels and autoplay on multimedia content helps put the user in control of their site experience.
  • Accessibility overlays: Websites with an accessibility overlay can actually make it trickier for screen reader users to read content. They sometimes disrupt screen readers from interpreting the page correctly and pose an obstacle to effective navigation. If your website has an accessibility overlay installed, it’s very important to check that it works properly with screen reader testing, or you could be excluding the very people you’re trying to include. 

How to use JAWS and NVDA for screen reader testing: 17 steps checklist

Because of the differences between various screen reader technologies, it’s a good idea to test your content on a variety of screen readers, such as JAWS and NVDA. One screen reader test per operating system is also best practise, so you might also want to consider testing on VoiceOver, which is designed to work with Mac OS/iOS.

JAWS is the most commonly used screen reader, so it’s a good starting point for your screen reader testing. It’s also one of the most expensive for users to purchase, so it makes sense to test it along a more widely accessible technology, like NVDA.

NVDA is a free and popular screen reader designed to work with Windows. It enables its user to access web content as speech or as a Braille display.

Once you’ve picked which screen readers you will test your content with, you should run through this checklist to test their compatibility with your site:

  1. Install your chosen screen reader. For NVDA head to their website for a free download. JAWS requires a license to run, which can be purchased on their website
  2. Select the browser you want to test it on
  3. Use keyboard shortcuts to read through your website's content and recreate the screen reader user journey from start to finish. You should navigate through the following actions:
  4. Check for missing/improper headings on your pages
  5. Check whether the HTML document has a language attribute (this ensures it will read content in the right accent and with the correct pronunciation for the desired region)
  6. Complete a fill form – are the labels and prompts working as expected?
  7. Interact with call-to-action buttons
  8. Interact with data tables – they should only be used for tabular data if present
  9. Check image alt text for descriptiveness
  10. Check link text for descriptiveness
  11. Check button text for descriptiveness
  12. Check common problematic elements, like CAPTCHA, accessibility overlays, unexpected screen changes and Flash content
  13. Check that the search functionality is present and functional
  14. Check for presence of ‘skip to main content’ and ‘skip navigation’ links
  15. Check that automatic carousels and autoplay are disabled
  16. Repeat the process with another type of screen reader
  17. Make the necessary accessibility fixes then repeat the screen reader testing to ensure your actions have been successful 

Many of these checks are simply web design best practices that will benefit all users, not just those who interact with your content using a screen reader.

How often should I test my website with screen readers? 

While automated tools are a great starting point for working towards web accessibility, knowing if your site is truly accessible to visitors who use a screen reader is only possible if you include screen reader testing in your accessibility audits – but how often should they take place?

As a general rule, screen reader testing should be conducted when you make any large-scale changes or additions to your website, like a website migration, redesign or as part of an accessibility audit. But it’s best to do it before you go live – rather than after. The insights you gain from early screen reader testing can help you with shaping your site development, rather than being addressed or added in retroactively.

Think of web accessibility as a process – not a one-off project. Every time you add new content to your site, you run the risk of introducing new accessibility barriers to screen reader users. While weekly screen reader testing is overkill, it’s a good idea to also incorporate regular screen reader testing into your scheduled website maintenance checks in case any serious errors have crept into your pages.

Is screen reader testing a requirement for WCAG compliance? 

While screen reader testing isn’t explicitly mandated for WCAG compliance, it’s accessibility best practice to incorporate manual screen reader checks into your website maintenance processes. WCAG does include several success criteria applicable to screen reader use, including: 

  • Non-textual content should have a “text alternative”.
  • The human language of each web page can be “programmatically determined” by a software application.
  • The human language of each passage or phrase on the web page can be programmatically determined.

Remember; the most effective method of ensuring web accessibility is a combined approach of designing clear, simple content, regularly testing your web pages with automated tests and screen readers and following the principles of WCAG across the entirety of your website. If you follow these steps your website will be a more inclusive space for everyone.

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