If you’ve spent any time around web accessibility, you’ve probably heard of WCAG, the Web Content Accessibility Guidelines. You may even know it has three conformance levels: A, AA, and AAA. And if you’re like most people in this field, including me, your day-to-day work rarely touches that third level.

That’s not an accident.

Most legal requirements, organizational policies, and client contracts point to Level AA as the target. AA has become the industry standard, and for good reason. It covers a meaningful range of accessibility needs without demanding things that most organizations can’t realistically deliver across an entire website.

But here’s the thing about Level AAA: the criteria that make it up aren’t arbitrary. Nobody designed them to be difficult or to give organizations something to aspire to on paper. Each one exists for a reason. The working groups that developed WCAG gave each one serious consideration.

So why does AAA get so little attention? A few reasons. WCAG itself acknowledges that full AAA conformance across an entire website is too difficult for most organizations to achieve as a general goal. Some criteria apply only to very specific types of content. Others demand time, budget, and specialized expertise that many organizations can’t provide. That’s why they landed at AAA rather than AA.

But “not required for full-site conformance” doesn’t mean “not worth understanding.”

For many organizations, certain AAA criteria are worth pursuing, depending on what they publish and who their audience is. Take a government agency that produces video content, a university with a strong Deaf student community, or a nonprofit focused on cognitive accessibility. For these organizations, some AAA criteria aren’t aspirational. They’re the right thing to do.

For accessibility professionals, understanding AAA criteria makes you better at your job. They shed light on the reasoning behind the A and AA criteria around them. They push you to think about users the baseline requirements don’t reach. They’re worth knowing.

The problem is that clear, useful explanations of AAA criteria are hard to find. The official WCAG Understanding documents are excellent, but they target a technical audience. Most accessibility blogs focus on A and AA. AAA criteria get a brief mention, or nothing at all.

That’s the gap this series aims to fill.

What this series is

This is a blog series covering every Level AAA success criterion in WCAG, one post at a time, in the order they appear in the specification.

Each post starts with the basics—what the criterion requires, who it helps, and why it matters—then works toward the technical details, including testing methodology and automated testing coverage.

A note on where I’m coming from

Accessibility has been part of my work since 2000, and for the past several years, it’s been all I do. And I’ll be honest: I am not an expert on Level AAA. Almost every audit I’ve done has targeted Level A and AA. AAA criteria rarely come up in client work. I know them, but I don’t get much practice with them, and the gaps show.

Part of why I’m writing this series is for myself. I want to dig into these criteria: understand the thinking behind them, what compliance looks like in practice, and where the real testing challenges are. Writing about something is one of the best ways I know to learn it.

So if you’re in the same boat, someone who knows accessibility well but hasn’t spent much time with AAA, you’re in good company. We’ll figure it out together.

Follow the series

Links will be added as each post is published. Criteria not yet covered are listed but not linked.

  • 1.2.6 Sign Language (Prerecorded)
  • 1.2.7 Extended Audio Description (Prerecorded)
  • 1.2.8 Media Alternative (Prerecorded)
  • 1.2.9 Audio-only (Live)
  • 1.3.6 Identify Purpose
  • 1.4.6 Contrast (Enhanced)
  • 1.4.7 Low or No Background Audio
  • 1.4.8 Visual Presentation
  • 1.4.9 Images of Text (No Exception)
  • 2.1.3 Keyboard (No Exception)
  • 2.2.3 No Timing
  • 2.2.4 Interruptions
  • 2.2.5 Re-authenticating
  • 2.2.6 Timeouts
  • 2.3.2 Three Flashes
  • 2.3.3 Animation from Interactions
  • 2.4.8 Location
  • 2.4.9 Link Purpose (Link Only)
  • 2.4.10 Section Headings
  • 2.4.12 Focus Not Obscured (Enhanced)
  • 2.4.13 Focus Appearance
  • 2.5.5 Target Size (Enhanced)
  • 2.5.6 Concurrent Input Mechanisms
  • 3.1.3 Unusual Words
  • 3.1.4 Abbreviations
  • 3.1.5 Reading Level
  • 3.1.6 Pronunciation
  • 3.2.5 Change on Request
  • 3.3.5 Help
  • 3.3.6 Error Prevention (All)
  • 3.3.9 Accessible Authentication (Enhanced)