Alt text
Also known as: Alternative text, alt attribute
Alt text is a short written description of an image that a screen reader reads out loud, so someone who can't see the image still gets its meaning.
In plain terms
Every meaningful image on a page should carry a few words that explain what it shows or does. A blind visitor using a screen reader hears those words instead of the picture. If an image is just decoration, you give it empty alt text so the screen reader skips it and doesn't clutter the page with noise.
Why it matters
Without alt text, screen-reader users hear "image" or a random file name — and any information the picture carried is lost. It's also the very first thing WCAG asks for (criterion 1.1.1), so missing alt text is one of the most common reasons a site fails an audit.
A "Buy now" button made from an image needs alt text like "Buy now" — not "button_final_v2.png". A chart needs a short summary of what the data shows, not just "chart".
Related terms
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