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What screen readers are - and why they are so important to accessibility testing

Blind people are only one of many groups of people with special needs. Still, to develop and test accessible websites, screen readers are considered the most important addition to a web developer's toolset. But why is that? And what are screen readers anyway?

What are screen readers?

A screen reader is a form of assistive technology which is essential to people who are blind, as well as useful to people who are visually impaired, illiterate, or have a learning disability. Screen readers are software applications that attempt to convey what people with normal eyesight see on a display to their users via non-visual means, like text-to-speech, sound icons, or a Braille device.

Screen reader (Wikipedia.org)

Why are they so important?

Screen reader tests are considered the "litmus tests" in the development of accessible user interfaces.

If you say that something is a litmus test of something, you mean that it is an effective and definite way of proving it or measuring it.

Litmus test definition and meaning (CollinsDictionary.com)

So to say, if a website can be read and operated by a screen reader, it can be considered pretty accessible. Screen reader compliant websites comply with a lot of requirements that are not only important to blind people, but also to many other groups of people with special needs.

In addition, while modern web browsers are pretty forgiving with malformed website code, screen readers tend to expose such weaknesses like invalid syntax or missing/wrong semantics pitilessly (if you haven't done this yet, go back and read Semantics provide meaning). So they are a good tool to test the overall quality and validity of the code.

Still, there are a few areas that cannot be validated with screen readers and thus need some special attention on their own (use of colour, contrasts, some audio and video requirements, just to name a few).


If you want to design modern accessible websites, you won't get around learning how to use screen readers. Our guide will be a huge help for this.