The complete guide to web accessibility
By The AsasWeb team 5 min read
Web accessibility means building a website that everyone can use, including people who rely on a keyboard, a screen reader, captions, or high contrast. The international standard is WCAG 2.2 at level AA, and it rests on four ideas, that pages must be perceivable, operable, understandable, and robust. Most of the work is foundational rather than cosmetic, the right HTML elements, a visible focus order, sufficient colour contrast, real text alternatives, and clear forms. Done from the start it costs little, widens your audience, reduces legal risk, and improves SEO at the same time.
Web accessibility is the practice of building websites that everyone can use, including people with disabilities. That covers a wide range of people: someone navigating with a keyboard instead of a mouse, a screen reader user who hears the page instead of seeing it, a person with low vision who needs strong contrast, and anyone watching a video with the sound off. This guide explains what accessibility means, why it is worth your attention, and how to get there without the jargon.
What accessibility actually means
The international reference is the Web Content Accessibility Guidelines, known as WCAG. The current version is WCAG 2.2, and most organisations aim for level AA, which is the level referenced by laws such as the European Accessibility Act. You do not need to memorise the guidelines, but it helps to know the four principles they rest on. A page should be:
- Perceivable. People can take in the content, whether they see it, hear it, or feel it. Images have text alternatives, video has captions, and text has enough contrast.
- Operable. People can use the page with whatever they have, a mouse, a keyboard alone, a switch, or voice. Nothing traps them and nothing depends on a sense or an action they cannot perform.
- Understandable. The content reads clearly and the interface behaves predictably, so people are not surprised or confused.
- Robust. The page is built so that browsers and assistive technologies, now and in the future, can interpret it reliably.
Almost everything practical in this guide maps back to one of those four ideas.
Who it is for
It is tempting to picture a small group of users, but accessibility is broader than that. Around one in six people lives with a significant disability, and many more benefit from accessible design without identifying as disabled: an older customer, someone with a temporary injury, a person on a slow connection, or anyone using a phone in bright sunlight. Building for the edges makes the experience better for the middle too. Captions help in a noisy room, strong contrast helps on a cheap screen, and a clear focus order helps anyone who prefers the keyboard.
The foundations that matter most
The good news is that the highest-impact work is structural, not decorative. Get these foundations right and you are most of the way to AA.
Use the right HTML element
A real button, a real link, and a real list each come with behaviour and meaning built in, for free. Rebuild them from generic styled boxes and you have to add focus, keyboard support, and the correct announcement back by hand, and most teams miss a piece. This is the single highest return habit in accessibility. We cover it in detail in why semantic HTML still matters.
Make everything work from the keyboard
Many people never use a mouse. Every control should be reachable and operable with the keyboard alone, in a logical order, with a focus outline you can actually see. It is also the fastest manual test you can run on your own site. See keyboard navigation, the test most sites fail.
Choose colours that everyone can read
Text needs enough contrast against its background, and colour must never be the only way you signal meaning. This is one of the most common failures and one of the easiest to fix once you know the targets. Our guide to choosing accessible colour contrast walks through the numbers.
Write real text alternatives
Images that carry meaning need alternative text so screen reader users get the same information, and decorative images need to be marked as decorative so they are skipped. Good alt text helps search engines understand your images too. See alt text for SEO and accessibility.
Build forms people can complete
Forms are where many visitors decide to become customers, so a confusing or inaccessible form costs you directly. Labelled fields, clear errors, and sensible grouping help everyone finish. We explain how in accessible forms win more leads.
Why it is good for your business
Accessibility is often framed as compliance, but it is first of all a larger audience and a better experience. An accessible site reaches more customers, converts more of them, and exposes you to less legal risk as accessibility laws tighten across the European Union and beyond. We make the commercial case in accessibility is good for business.
There is a quiet bonus too. The same structure that helps assistive technology, meaningful headings, real landmarks, descriptive links, and proper alternatives, is exactly what search engines read to understand a page. Accessibility and SEO are built on the same foundations, so the work pays off twice.
A note on e-commerce
Online shops have specific pressure points: product galleries, filters, variant pickers, and a checkout that must not lose anyone. An inaccessible checkout is an abandoned sale. If you sell online, the e-commerce accessibility checklist covers the parts that matter most.
How to test
You do not need a lab to start. A short, repeatable routine catches most issues:
- Put the mouse away and move through the whole page with the Tab key. Can you reach and use everything, and can you always see where you are?
- Run an automated checker such as axe or Lighthouse. It will not catch everything, but it flags the obvious failures fast.
- Check your colour contrast against the AA targets.
- Try a screen reader for ten minutes. On most systems one is already built in.
Automated tools find perhaps a third of issues, so pair them with the manual checks above. The goal is not a perfect score, it is a site that a real person can actually use.
Where to start
If this feels like a lot, start with the foundations: correct HTML, a working keyboard order, and sufficient contrast. Those three alone remove most barriers. From there, work through alt text, forms, and the rest as a steady habit rather than a one-off project.
If you would like a hand, accessibility is built into everything we do, and we offer it as a focused service too. See web accessibility, or start a project and tell us where your site stands today.