Want AI to understand your website? Start with accessibility.
Why semantic HTML and content structure matter more than ever in the age of ChatGPT
As organisations scramble to understand Answer Engine Optimisation (AEO), many are looking for new tactics to improve how their content appears in AI-generated answers.
What if some of the most important foundations have been sitting in accessibility guidelines for years?
WCAG wasn't designed for search engines or large language models. It was designed to help people access and understand digital content regardless of ability. Yet many of the practices it promotes create exactly the kind of structured, meaningful content that machines rely on to interpret information.
Machines need structure, just like people do
Search engines and AI systems don't "read" a page in the same way humans do.
They rely on signals that help them understand hierarchy, relationships and meaning. The clearer those signals are, the more confidently they can determine what a page is about.
Many WCAG-aligned practices improve those signals naturally.
A well-structured page is easier for a screen reader to navigate. It's also easier for an AI system to parse and understand.
Heading structures create meaning and hierarchy
One of the simplest accessibility recommendations is to use headings correctly.
A page should have a logical structure:
- H1 for the primary topic
- H2s for major sections
- H3s for subsections
For a screen reader user, this provides navigation and context.
For an LLM, it provides an outline of the page's information architecture.
Consider the difference between these two structures:
Poor structure
- Benefits
- Costs
- Conclusion
Accessible structure
- H1: Renewable Energy Grants
- H2: Eligibility Criteria
- H2: Available Funding
- H2: Application Process
- H2: Deadlines
The second version makes relationships explicit. Both people and machines can understand the topic hierarchy immediately.
Descriptive links provide context
WCAG encourages link text that describes the destination or purpose of the link.
Instead of:
- Click here
- Read more
- Learn more
Use:
- Download the sustainability audit report
- View our Health and Safety compliance checklist
- Read our guide to creating impactful on-brand messaging
Screen reader users often navigate pages by links alone. Generic link text becomes meaningless when taken out of context.
The same principle applies to AI systems. Descriptive links contribute additional semantic information about the surrounding content and destination.
Above
Generic links obscure information about the surrounding content and destination, from humans and machines alike.
Alternative text adds information that would otherwise be lost
Alternative text is often treated as a compliance exercise.
In reality, it's a mechanism for communicating information that exists outside the page's visible text.
A chart showing rising customer satisfaction might have alt text such as:
"Customer satisfaction increased from 72% in 2021 to 91% in 2024."
Without that description, both assistive technologies and automated systems lose access to potentially valuable context.
Good alt text doesn't simply describe images. It communicates meaning.
Semantic HTML reduces ambiguity
Accessibility guidelines encourage the use of semantic HTML elements such as:
<nav><main><article><section><header><footer>
These elements define the role and purpose of content.
A screen reader uses these landmarks to help users navigate.
Machines use the same information to understand the structure of a page and the relationships between different pieces of content.
Semantic markup reduces ambiguity, which is valuable for both accessibility and machine interpretation.
Clear language improves understanding
WCAG encourages content that is readable and understandable.
Short sentences, clear terminology, defined acronyms, consistent language.
These practices reduce cognitive load for users — they also reduce interpretive load for machines.
AI systems perform best when information is explicit, unambiguous and well organised. Content written for clarity tends to generate more accurate summaries, answers and citations.
Accessibility and Answer Engine Optimisation are different disciplines with different goals, yet both depend on the same underlying principle
Accessibility and AEO share the same foundation
Accessibility and Answer Engine Optimisation are different disciplines with different goals.
Accessibility exists to ensure digital experiences work for everyone.
AEO exists to improve how content is understood and surfaced by AI systems.
Yet both depend on the same underlying principle:
Information should be structured, meaningful and easy to interpret.
That's why the overlap between WCAG and AEO is so significant.
The organisations investing in accessible content aren't simply improving compliance. They're creating content that is easier for people, search engines and AI systems to understand.
As AI becomes a more important gateway to information, the case for accessibility looks stronger than ever.
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