Accessibility is primarily about equity and compliance; SEO benefits are a side effect of clearer structure and content. Still, many best practices serve both.
Semantic structure
Use one H1 per page and nest headings logically. Screen reader users and search engines both rely on that outline to understand sections.
Alt text and media
Describe informative images; keep decorative images out of the accessibility tree. Transcripts and captions make video content quotable and indexable.
Readability
Sufficient contrast and readable font sizes reduce bounce and support comprehension—signals that align with quality content.
Forms and errors
Clear labels, error messages, and focus management help users complete tasks; completed tasks mean conversions, not frustrated exits.