Intro to Accessibility

What is web accessibility?

Web accessibility means making sure your websites, apps and digital tools work for everyone. It means designing and coding so that people with different abilities can see, understand, navigate and use what you've built.

Being accessible doesn't mean building separate versions for different people. Your aim is to create one experience that works for everyone, regardless of their abilities.

So at its core, accessibility removes barriers. When you do it right, all users can access the same information, complete the same tasks and have equivalent experiences. Simple as that.

The POUR principles

Web accessibility is built on four principles. They spell out POUR, which makes them easy to remember:

• Perceivable. People need to be able to perceive your content through at least one of their senses. This means adding text alternatives for images, making sure there's enough colour contrast and ensuring content can adapt to different formats.
• Operable. People need to be able to use your interface and navigate your site. Everything should work with a keyboard, users should have enough time to complete tasks and you should avoid content that could trigger seizures.
• Understandable. Your information and interface need to be clear. That means writing text that's understandable by everyone, making things behave predictably and helping people avoid and fix mistakes.
• Robust. Your content should work reliably across different browsers, devices and assistive technologies. Both now and in the future. It means using well-structured, standards-compliant code.

Who does accessibility affect?

Hint: way more people than you probably think.

About 1.3 billion people worldwide(Opens external link in new tab), or 16% of everyone, live with some form of disability. In the United States alone, that's over 29% of adults. These aren't niche groups. They're significant chunks of your potential audience.

And they've got serious spending power. Globally, people with disabilities and their families control $13 trillion in annual disposable income(Opens external link in new tab). In the UK, households with members that have disabilities spend £274 billion every year. In the U.S., working-age adults with disabilities have roughly $490 billion in annual purchasing power.

It's not just about permanent disabilities

Accessibility helps far more people than those with permanent disabilities. Think about these situations:

• Temporary impairments. Someone recovering from eye surgery. A broken arm. Side effects from medication. These are all temporary, but they create real barriers.
• Situational limitations. Ever tried to use your phone in bright sunlight? Or navigate a website with one hand whilst holding a baby? Or dealt with a rubbish internet connection? That's situational disability.
• Ageing. As we get older, our vision, hearing, dexterity and cognition change. Age-related changes affect all of us eventually.
• Everyone, really. Clear navigation, readable fonts and well-structured content make things easier for absolutely everyone. No exceptions.

The numbers back this up. Research shows that 60% of all consumers(Opens external link in new tab) have abandoned purchases because of poor website experience. For people with disabilities, 69% will leave a website if they hit accessibility barriers.

Here's my point.

You're not just helping people with disabilities. You're making things better for everyone.

Types of disabilities and their impact

Let's talk about what different disabilities actually mean for your users.

• Visual disabilities include blindness, low vision and colour blindness. People might use screen readers, screen magnification or high contrast settings. Common problems include poor colour contrast, images without alternative text and content that doesn't resize properly.
• Hearing disabilities affect how people access audio content. A video without audio descriptions and no captions or transcript will not be understood properly.
• Motor disabilities impact how people interact with devices. Some can't use a mouse at all. They rely entirely on keyboards, voice commands or specialised input devices. Small clickable areas, time limits and mouse-only functionality create massive barriers.
• Cognitive disabilities affect how people process and understand information. Complex language, inconsistent navigation, cluttered layouts and unpredictable behaviour all create challenges. This includes dyslexia, ADHD, autism and various learning disabilities. You'll often hear others refer to these as invisible disabilities.

Accessibility is delivery risk

Accessibility problems rarely stay contained. When teams find them late, they interrupt releases, create repeat work and leave people unable to complete important tasks.

Building accessibility into everyday work reduces that risk. It helps teams find defects earlier, assign responsibility and keep quality steady as product and team grow.

• Late defects disrupt releases. A keyboard trap in checkout or an error message that a screen reader misses can block a care flow. Finding it before release is cheaper and less disruptive than rushing out a fix after customers report it.
• Repeated fixes drain delivery time. When teams treat accessibility as a final check, the same issues return with each new feature. Build checks into design, development and review so fixes stick.
• Clear ownership prevents gaps. If nobody knows who tests accessibility or when, problems move between teams until release exposes them. Agree who owns each check and what happens when it fails.
• Support requests reveal quality problems. Confusing forms, unclear errors and awkward navigation make people ask for help or abandon a task. Fixing root causes reduces support work and makes key flows more reliable.
• Good process scales with your team. Shared standards, checks and responsibility let new people ship consistent work without rediscovering the same problems.

Accessibility is one source of product and delivery risk. Manage it early and your team spends less time reacting to defects and more time shipping dependable work.

Understanding the standards: WCAG and conformance levels

The Web Content Accessibility Guidelines (WCAG)(Opens external link in new tab) are the globally recognised standard for digital accessibility. They're developed by the World Wide Web Consortium (W3C) through the Web Accessibility Initiative (WAI)(Opens external link in new tab).

WCAG versions

WCAG 2.1 is currently referenced by most legal frameworks worldwide. WCAG 2.2, approved as an ISO/IEC international standard in October 2025, includes additional success criteria and represents the most current version. WCAG 3.0 is in development, but it's not ready yet.

Newer versions of the WCAG don't replace older ones. They build on them. For example, WCAG 2.2 includes everything from WCAG 2.1, plus nine additional criteria.

The three conformance levels

WCAG organises its requirements into three levels: A, AA, and AAA.

• Level A is the bare minimum. If your website doesn't meet Level A, it probably has serious accessibility issues that stop people with disabilities from using it at all. This level covers basics like providing text alternatives for images, making sure everything works with a keyboard and ensuring content works with assistive technologies.
• Level AA is what most organisations should aim for. It addresses a wider range of accessibility issues and provides more comprehensive coverage. Most legal frameworks, including the ADA and Section 508, reference Level AA. This includes things like sufficient colour contrast, consistent navigation and clear error messages.
• Level AAA is the highest level. Whilst it represents the ideal, it's often not required and can be difficult to achieve for all content. Even W3C says Level AAA shouldn't be required as a blanket policy for entire sites.

Getting started in one day

You don't need to become an accessibility expert overnight. Here's how to make meaningful progress today:

• Morning: Learn the basics. Read through the W3C's Introduction to Web Accessibility(Opens external link in new tab). It should take you about 30 minutes. Then check out The A11Y Project's checklist(Opens external link in new tab) to see what good looks like. Another 30 minutes.
• Midday: Test your site. Install the WAVE browser extension(Opens external link in new tab) and run it on your key pages. It'll flag obvious issues. Try navigating your site using only your keyboard (Tab, Enter and arrow keys). Can you access everything? See how much you can get through in one hour.
• Afternoon: Fix quick wins. Add alt text to images. Check your colour contrast using WebAIM's Contrast Checker(Opens external link in new tab). Make sure your buttons and links have clear, descriptive text. Don't stress. Just set a time limit of two hours and see where that takes you.
• End of day: Make a plan. Document what you found. Share it with your team. Identify who's responsible for accessibility in your process. Book a follow-up session to tackle bigger issues. You could probably get it done in one hour.

That's it. One day to understand the problem, spot issues, make improvements and start building accessibility into your process.

My own free resources

I have a bunch of free resources you can use to get started as well.

• Glossary of confusing terms. It can be confusing to read about WCAG, conformance, ADA, ARIA, POUR and many other jargony terms and not understand what the hell they mean.
• Accessibility checklists. Handy printouts you can use to check your work for major accessibility issues without feeling intimidated.
• Six days to an accessible website. A free six day email course will teach you how to get the upper-hand on 1 million websites by fixing the most common accessibility issues on yours.

Where to go from here

Start with the basics. Run simple tests on your current product and prioritise issues that stop people completing key tasks. Then agree who checks accessibility, when they check it and what happens when they find a problem.

Your team doesn't need to know everything on day one. Give people knowledge, tools and support, then build accessibility into design, development and review. That keeps defects from piling up as you ship.