Accessibility is often treated as an afterthought, but it should be part of how you build from the start. When I first learned about web accessibility, I realized how many barriers I was creating without even knowing it. Making applications accessible isn't just the right thing to do—it's also good for business and often required by law.

Web accessibility means making your website usable by people with disabilities. This includes people who are blind or have low vision, people who are deaf or hard of hearing, people with motor disabilities, and people with cognitive disabilities. But accessibility benefits everyone—clear navigation and good contrast help all users.

Why accessibility matters

Accessibility is a legal requirement in many places. Laws like the Americans with Disabilities Act in the US and similar laws in other countries require websites to be accessible. Lawsuits over inaccessible websites are becoming more common, and the cost of making a site accessible after it's built is much higher than building it accessible from the start.

But beyond legal requirements, accessibility is good for business. Accessible websites work better for everyone. They're easier to use, they rank better in search engines, and they work on more devices. Making your site accessible can expand your audience significantly.

Accessibility also improves code quality. Accessible code is usually cleaner, more semantic, and easier to maintain. The practices that make code accessible also make it better structured.

Semantic HTML

The foundation of accessibility is semantic HTML. Use the right HTML elements for their intended purpose. Use headings to structure content, buttons for actions, links for navigation, and form elements for inputs.

Screen readers rely on semantic HTML to understand and navigate your page. If you use a div with a click handler instead of a button, screen readers won't know it's clickable. If you use a div instead of a heading, screen readers won't understand the content hierarchy.

Semantic HTML also helps with keyboard navigation. Native HTML elements work with keyboards out of the box. If you build custom components, you need to add keyboard support yourself, which is easy to get wrong.

Keyboard navigation

Many users navigate websites using only a keyboard. This includes people who can't use a mouse, people who prefer keyboards, and people using assistive technologies. Your website should be fully usable with just a keyboard.

All interactive elements should be reachable and usable with the keyboard. Users should be able to tab through your page and activate buttons, links, and form controls. The tab order should be logical and follow the visual layout.

Focus indicators are important. Users need to see where they are on the page. Browsers provide default focus styles, but they're often removed by CSS resets. Make sure your focus indicators are visible and clear.

ARIA attributes

ARIA, or Accessible Rich Internet Applications, provides additional information to assistive technologies. Use ARIA when HTML alone isn't enough. But don't use ARIA when native HTML would work—prefer semantic HTML over ARIA.

ARIA roles describe what an element is or does. ARIA properties provide additional information about an element. ARIA states describe the current state of an element, like whether it's expanded or collapsed.

Use ARIA labels to provide names for elements that don't have visible text. Use ARIA descriptions to provide additional context. But be careful not to overuse ARIA—too much can be overwhelming for screen reader users.

Color and contrast

Color shouldn't be the only way to convey information. If you use color to indicate an error, also use text or an icon. Some users can't distinguish colors, so they'll miss information that's only conveyed through color.

Contrast ratios are important for readability. Text needs sufficient contrast against its background. The WCAG guidelines specify minimum contrast ratios: 4.5:1 for normal text and 3:1 for large text.

There are tools that can check contrast ratios for you. Use them during development to make sure your text is readable. This is especially important for links and buttons, which need to stand out from regular text.

Images and media

Images need alt text that describes what's in the image. This helps screen reader users understand images they can't see. Decorative images should have empty alt text, but informative images need descriptive alt text.

Videos should have captions for users who are deaf or hard of hearing. Captions also help users who can't play audio, like in quiet environments. Transcripts are also valuable and can improve SEO.

Forms and inputs

Forms are a common source of accessibility problems. Labels should be properly associated with inputs using the for attribute or by wrapping the input in a label. This helps screen readers understand which label goes with which input.

Error messages should be clear and associated with the relevant input. Use ARIA attributes to connect error messages to inputs so screen readers can announce them.

Required fields should be clearly indicated, and validation should happen in a way that's accessible. Don't rely on color alone to indicate errors—use text and icons as well.

Testing for accessibility

Testing is important to catch accessibility issues. Automated tools can catch some problems, but they can't catch everything. Manual testing with keyboard navigation and screen readers is essential.

Try navigating your site using only a keyboard. Can you reach all interactive elements? Is the tab order logical? Can you complete all tasks without a mouse?

Screen reader testing helps you understand how your site sounds to users who rely on screen readers. You don't need to become an expert, but spending some time with a screen reader will help you understand common issues.

The bottom line

Accessibility isn't optional—it's a requirement. But it's also an opportunity to build better applications that work for more people. Start with semantic HTML, ensure keyboard navigation works, and test with assistive technologies.

Building accessible applications from the start is easier than retrofitting accessibility later. Make it part of your development process, and you'll build better applications for everyone.