What is Alt Text?

Alt text is the written alternative for an image, carried in the alt attribute of the HTML image element. Assistive technology reads it instead of the picture, browsers display it when an image fails to load, and search engines use it as one signal for interpreting visual content. In a storefront the attribute applies to product photography, category banners, size charts rendered as images, payment and delivery icons, and campaign visuals. Although the attribute is often called an alt tag, it is an attribute of an element and not a tag of its own.

Definition

The Web Content Accessibility Guidelines require a text alternative for non-text content under success criterion 1.1.1 at conformance level A. The rule is not to describe every image but to convey the same purpose: an informative product photo needs a specific description, a decorative image takes an empty alt attribute so that assistive technology skips it, and an image used as a link describes the destination rather than the picture. In the European Union the European Accessibility Act extends accessibility obligations to consumer facing e-commerce services. Keyword stuffing in alt text serves neither audience and can be judged as manipulative.

Why it matters

In a composable storefront images arrive from a PIM, a DAM, or a CMS, so the alternative text belongs next to the asset in that system and travels through the API with the image URL, localised per market like any other content field. Frontend components should treat the value as a required prop rather than deriving it from a file name, and images with no supplied text should render an empty attribute instead of a placeholder. Responsive image pipelines that generate several renditions must keep one alternative per asset, and lazy loading must never postpone the attribute itself.

Use cases

On product detail pages each gallery image describes what distinguishes it, such as a back view, a fabric close-up, or a scale reference. On listing pages the alternative usually repeats the product name and the depicted variant, which keeps tile markup readable without noise. Banners that carry an offer in the graphic need the offer restated in text, otherwise the message is lost when images are unavailable. Editorial content, lookbooks, and user generated galleries follow the same rule, while purely decorative separators and background textures stay silent with an empty attribute.

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