The Ultimate Guide to Web Accessibility

May 20, 2025

TL;DR Accessibility is not a checkbox—it’s an ongoing quality practice that benefits every user.
This guide gives you a soup-to-nuts roadmap for building, testing, and maintaining accessible web experiences in 2025 and beyond.
Each chapter links to deep-dive articles for hands-on samples and advanced techniques.

Why Accessibility Matters
Regulations & Standards
Semantic Foundations
Keyboard Navigation & Focus
Visual Design & Color Contrast
Rich Media & Motion
Forms & Error Handling
Dynamic UI & ARIA
Testing & Continuous Integration
Performance & Accessibility
Governance & Culture
Next Steps

Why Accessibility Matters

1 in 6 people worldwide live with some form of disability (visual, auditory, motor, cognitive).
Accessible sites load faster and rank higher, because semantic HTML improves SEO and Core Web Vitals.
Legal risk is rising: the EU EAA can fine up to 4 % of global turnover; U.S. ADA lawsuits increase every year.

ROI: A Microsoft study showed that every 1 % accessibility improvement reduced support tickets by 4 %.

Regulations & Standards

Region	Primary Law	Standard	Deadline
EU	EAA (2019/882)	WCAG 2.2 AA	28 Jun 2025
US	ADA Title III + §508	WCAG 2.2 AA	Ongoing
Canada	AODA	WCAG 2.2 AA	1 Jan 2026

WCAG 2.2 Highlights

New AA criteria:

ID	Name	Key Point
2.2.4	Animation from Interactions	Users must be able to disable motion.
2.2.5	Target Size (Minimum)	Touch/click targets ≥ 44 × 44 px.
2.4.11	Focus Appearance	Visible focus outline ≥ 3 : 1 contrast ratio.

Semantic Foundations

Using semantic HTML is the fastest win: native elements carry built-in keyboard, ARIA roles, and screen-reader support.

<!-- ✗ Anti-pattern -->
<div class="btn" onclick="save()">Save</div>

<!-- ✓ Semantic -->
<button type="button" class="btn-primary" onclick="save()">Save</button>

Landmark Elements

Tag	ARIA Role	Purpose
`<header>`	`banner`	Site or section header
`<nav>`	`navigation`	Primary navigation links
`<main>`	`main`	Unique page content
`<aside>`	`complementary`	Sidebar / related links
`<footer>`	`contentinfo`	Copyright & legal

Deep dive → Semantic HTML for Accessibility

Keyboard Navigation & Focus

If a user can’t complete a task with only the keyboard, you fail WCAG A.

Logical order follows DOM source.
Visible focus — never hide outlines.
Provide a Skip Link:

<!-- Adds a visible skip link only when focused -->
<a class="sr-only focus:not-sr-only" href="#main">
  Skip to main content
</a>

Deep dive → Keyboard Navigation Best Practices

Visual Design & Color Contrast

Context	Minimum Ratio
Normal text	4.5 : 1
Large/bold text (≥ 24 px or 18 px bold)	3 : 1
Non-text UI (icons, borders)	3 : 1

Use Figma plugins or Tailwind contrast utilities to enforce ratios.

Rich Media & Motion

Media	Requirement	WCAG ref
Images	Descriptive `alt` text	1.1.1
Video	Captions & transcript	1.2.2 / 1.2.3
Audio	Transcript	1.2.1
Motion	Respect `prefers-reduced-motion`	2.2.4

/* Disable animations for users who prefer reduced motion */
@media (prefers-reduced-motion: reduce) {
  .spin       { animation: none; }
  .fade-in    { animation: none; }
  .parallax   { transform: translateZ(0); }
}

Forms & Error Handling

Every input has a <label> with for + id.
Inline errors announced via ARIA-live:

<form id="signup" novalidate>
  <label for="email">Email</label>
  <input id="email" name="email" type="email" required />

  <div id="email-error"
       role="alert"
       aria-live="assertive"
       class="text-red-600 mt-2">
    <!-- Error message injected here -->
  </div>

  <button type="submit">Sign up</button>
</form>

Validate on submit and blur, not on every key-press.

Dynamic UI & ARIA

“No ARIA is better than bad ARIA.” — WAI

Accessible Tabs (minimal pattern)

<!-- Tabs -->
<div role="tablist" aria-label="Billing options">
  <button id="basic-tab"
          role="tab"
          aria-selected="true"
          aria-controls="basic-panel">
    Basic
  </button>

  <button id="pro-tab"
          role="tab"
          aria-selected="false"
          aria-controls="pro-panel">
    Pro
  </button>
</div>

<!-- Panels -->
<section id="basic-panel"
         role="tabpanel"
         aria-labelledby="basic-tab">
  …Basic plan details…
</section>

<section id="pro-panel"
         role="tabpanel"
         aria-labelledby="pro-tab"
         hidden>
  …Pro plan details…
</section>

Deep dive → ARIA Roles Explained

Testing & Continuous Integration

Layer	Tools	Coverage
Static lint	ESLint `jsx-a11y`, Stylelint	~20 %
Automated UI	Axe-core, Pa11y, Lighthouse-CI	40–50 %
Manual	NVDA, VoiceOver, keyboard	Remaining

GitHub Actions sample

name: accessibility-check
on: [pull_request]

jobs:
  axe-scan:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Install dependencies
        run: npm ci

      - name: Run A11 against local build
        run: |
          npx @a11ysprint/cli scan http://localhost:3000 \
            --output ci-report.html \
            --fail-on critical

Block merges on critical issues; auto-open tickets for major.

Performance & Accessibility

Fast pages help users with cognitive and motor impairments.

Metric	Target	Quick Fix
LCP	< 2.5 s	Lazy-load images, preconnect fonts
CLS	< 0.1	Reserve space, avoid FOUT
TBT	< 200 ms	Split bundles, web-workers

Governance & Culture

Assign an Accessibility Champion per squad.
Set an OKR: “≤ 5 critical issues per release.”
Conduct quarterly manual audits and team training.

Next Steps

Run a free WCAG 2.2 scan → Start now
Dive into the cluster articles linked above.
Integrate our CLI into CI.
Share this guide with your team and book a 5-Day Accessibility Sprint if you’re racing the EAA deadline.