Alt Text Checker
Checks <img> elements for alt text like Lighthouse. Decorative images (empty alt, role="presentation|none", or aria-hidden="true") are exempt.
Results
Enter a URL or paste HTML, then run the audit.
Why alt text matters (accessibility, search & AI)
- Accessibility (A11y): Alt conveys the purpose of images to screen reader users; decorative images should be hidden with empty
altor presentation roles. - Search: Alt helps search engines understand images and can improve image search visibility and accessibility best practices for pages.
- LLMs & Vision AI: Clear, descriptive alt (or nearby captions) provides machine-readable context that improves multimodal understanding and summary quality.
FAQs: alt text for SEO, LLMs & accessibility
When the image is purely decorative. Use
alt="", or role="presentation"/role="none", or hide with aria-hidden="true". See the W3C WAI Alt Decision Tree.
Describe the purpose or essential content concisely. Avoid “image of…”. If the surrounding text already states the same info, alt can be shorter (or empty if truly redundant).
It helps search engines understand images and can aid image search visibility; it’s part of good accessibility and helpful content practices, not a magic ranking lever by itself.
Many multimodal systems read HTML text alternatives (alt/captions). Clear alt text improves machine understanding and summaries for users relying on assistive tech or AI previews.
Alt applies to
<img>. For inline <svg role="img">, use a child <title>/<desc>. CSS background images have no alt; convey meaning in nearby text if needed.