Accessibility testing

What is accessibility testing?

Accessibility testing examines whether a website, application, or digital product is usable by everyone, including people with disabilities. The goal is to ensure no one is excluded from the digital experience – whether they are blind, visually impaired, mobility-impaired, hearing-impaired, or have cognitive difficulties.

Accessibility is not just a moral obligation but also a legal requirement in many countries, including the European Union (Web Accessibility Directive, European Accessibility Act).

Why is accessibility important?

Who do we create accessible interfaces for?

• Blind and visually impaired users – who use screen readers or browse in magnified view
• Mobility-impaired individuals – who cannot use a mouse, only keyboard or special devices
• Hearing-impaired people – who need captions and visual cues
• People with cognitive difficulties – who need simple, understandable content
• Older adults – whose vision, hearing, or motor skills decline
• Temporarily impaired users – e.g., broken arm, eye condition, noisy environment

Accessibility can affect anyone!

Many think accessibility only matters to a narrow group. This is a misconception!

For example:

• Broken arm – can only navigate with keyboard
• Reading on tablet in sunlight – low contrast is hard to see
• In a noisy environment – watch video with captions
• Limited mobile data – disable images, load text only
• Getting older – harder to see, slower to react

Accessible design creates a better user experience for everyone: clearer structure, easier navigation, more understandable content.

When and where should you test for accessibility?

Mandatory testing

• Financial services – banks, insurance companies (critical for universal access)
• Public services and government sites – legal requirement
• E-commerce sites – high traffic, wide audience
• Educational platforms – inclusive education
• Media content – news, videos, streaming platforms

Recommended testing

Practically all web and mobile applications, because it:

• Increases target audience
• Improves SEO rankings (Google rewards it)
• Reduces legal risks
• Enhances brand image
• Provides better user experience for everyone

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Accessibility testing tools and software

Accessibility testing is built on three main pillars:

1. Automated tools – quick overview, error identification
2. Manual keyboard testing – usability verification
3. Screen reader testing – real user experience

Screen reader software

Browser extensions

Online Tools

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WCAG Standards

The WCAG (Web Content Accessibility Guidelines) is a standard developed by the W3C.

WCAG Levels:

• Level A – minimal accessibility
• Level AA – recommended (required by most regulations)
• Level AAA – maximum accessibility

Four Principles (POUR):

1. Perceivable – Content must be perceivable
2. Operable – Operable with keyboard
3. Understandable – Understandable content
4. Robust – Compatible with various technologies

WCAG quick reference: https://www.w3.org/WAI/WCAG21/quickref/

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Testing process step by step

1 Preparation

Tools: NVDA/VoiceOver, browser extensions (axe, WAVE, Silktide)

Environment: Different browsers and devices

2 Automated check

1. Lighthouse Audit: F12 → Lighthouse → Generate report
2. axe or Silktide: Full page scan, analyze issues
3. WAVE: Visual feedback, contrast check

3 Keyboard navigation

Tab navigation:

• Tab through all interactive elements
• Is the focus order logical?
• Is focus indicator visible?
• Any keyboard traps?

Interactions:

• Links: Work with Enter?
• Buttons: Work with Enter/Space?
• Modals: Close with Escape?
• Forms: Can be filled with keyboard only?

4 Screen reader testing

Structure:

• NVDA + F7 or VO + U – Elements list
• Is heading hierarchy logical? (H1 → H2 → H3)
• Are there landmarks?

Navigation:

• H – Navigate headings
• K – Links (descriptive text?)
• F – Form fields (has label?)
• G – Images (has alt text?)
• T – Tables

5 Testing checklist

6 Common issues and solutions

Issue	Problem	Solution
Missing alt text	Screen reader can't describe image	<img alt="Descriptive text">
Wrong heading order	Confusing navigation	Follow H1 → H2 → H3 order
"Click here" link	Meaningless without context	Use descriptive text
Unlabeled input	Don't know field purpose	<label for="...">
Low contrast	Hard to read	Min. 4.5:1 ratio
Mouse-only usable	Keyboard users excluded	Tab + Enter functionality
Focus trap	Cannot exit area	ESC/Tab handling

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Tips for beginners

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Further information

Useful links

• W3C WAI: https://www.w3.org/WAI/
• WebAIM: https://webaim.org/
• The A11Y Project: https://www.a11yproject.com/
• MDN Accessibility: MDN Docs

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