Accessibility Explained: Definition, Examples and Tips

Imagine you want to book a train ticket late in the evening. The “Next” button is light gray on white, the date picker only works with a mouse, and an error shows up as a thin red border with no text. Annoying, but doable.

Now imagine the same page for someone who is blind and uses a keyboard and speech output. For them, the booking ends right at those spots. Accessibility is what keeps that from happening.

Explained simply

Accessibility means designing digital products such as websites, apps or PDFs so that everyone can perceive, understand and operate them, including people with disabilities. You’ll often see it shortened to “a11y,” because there are eleven letters between the a and the y.

Think of a ramp next to a staircase. It helps wheelchair users, but it also helps anyone with a stroller or a suitcase. Digital accessibility works the same way. The W3C’s Web Accessibility Initiative explicitly lists people without disabilities who benefit too: older adults, people with a broken arm, and anyone using their phone in bright sunlight or with the sound off.

What kinds of barriers exist

According to the World Health Organization (WHO), around 1.3 billion people worldwide live with a significant disability, roughly one in six. Their obstacles online vary a lot:

Vision: Blind people use a screen reader that reads content aloud. People with low vision zoom in or need strong contrast.
Hearing: Videos without captions are silent for deaf people.
Motor: People who can barely move their hands use a keyboard, voice control or switch devices. Tiny click targets become a real obstacle.
Cognition: Convoluted sentences, unclear flows and tight time limits overwhelm people with learning disabilities or attention difficulties.

Rules and laws

The main benchmark is WCAG, the W3C’s Web Content Accessibility Guidelines. They define testable criteria, for example a contrast ratio of at least 4.5:1 for regular text.

In the EU, the European Accessibility Act (Directive 2019/882) extends accessibility requirements to many private companies. Germany implements it through the BFSG (Barrierefreiheitsstärkungsgesetz, roughly “Accessibility Strengthening Act”), which has applied since June 28, 2025. Beyond public bodies, it covers online shops, banks and booking platforms that serve consumers. Microenterprises that provide services are exempt. For details, read The BFSG in Practice: What Germany’s Accessibility Act Means for Websites and Apps.

An example

Here’s an example: a small delivery service has an order form whose fields are labeled only with placeholder text. As soon as someone starts typing, the hint disappears. The screen reader just announces something like “edit,” and the order button is an image with no alt text.

After a redesign, every field has a visible label, error messages explain in words what’s missing, and the button is a real button with text. For screen reader users, ordering becomes possible in the first place. And everyone else gets through faster, because they no longer have to guess.

Common misconceptions

Accessibility isn’t a niche extra, and it isn’t a box a plugin can tick. Overlay tools that add an accessibility toolbar don’t fix missing labels or keyboard traps. Accessible doesn’t mean boring, either: it’s about structure, contrast and clear interaction, not about giving up on visual design. To see why the topic goes far beyond colors, read Why Accessibility Is More Than Contrast and Font Size.

In practice

Put the mouse away. Use your website with only Tab, Enter and the arrow keys. If you can’t see where the focus is or you get stuck somewhere, you’ve found a barrier.
Check contrast while you design. Test color combinations before the design is final. Recoloring later takes far more effort.
Describe images meaningfully. Informative images need alt text that conveys their message. Purely decorative images get an empty alt attribute so screen readers skip them.

Related terms

WCAG, Screen Reader, Fitts’ Law

Accessibility