Accessibility and search engine optimization (SEO) might seem like separate priorities, but they share a common goal: improving the experience for all users. Accessibility ensures that websites are usable by people with disabilities, while SEO focuses on making content discoverable by search engines. Together, they form a powerful synergy, as many practices that enhance accessibility also improve search visibility.
There are a lot of cases where accessibility and SEO support each other really well. These are only a few of them.
Semantic HTML helps both assistive technologies and the users understand the page structure. Using semantic tags such as <header>, <article> and <nav> provides proper page structure.
Structuring your content with clear headings helps users navigate the content. The search engines also understand the content hierarchy better.
Instead of a text like "read more", provide more context to a link by using "read more about this important topic".
If a link or button text is understandable on its own regardless of the context it is in, the better it is.
Both users and search engines benefit from clear and descriptive link texts.
Alternative texts help screen reader users understand images. Search engines can read the alternative text as well.
Providing captions and transcripts helps the users understand video content. But these also allow search engines to index that content. Search engines cannot index video content.
While tables are very often problematic for accessibility, semantically correctly created tables help both users and screen readers understand the relationships and hierarchy of tabular data.
From the SEO perspective, responsive design and mobile optimization are the recommended ways to build services. This benefits also accessibility because responsive design better supports, for example, zooming.
Optimising for accessibility improves page load speed. And that is also a benefit for SEO.
Clear and predictable navigation helps users find their way on a site. It also improves crawlability because search engines favor clear site structure.
Unfortunately, there are some cases where SEO and accessibility don't align, at least not so well.
Sometimes SEO experts recommend filling the content with keywords, e.g. at the start of headings or the main content. For accessibility, the content focus is on clarity and usefulness, which might conflict with the keyword use.
SEO doesn't benefit at all from empty alternative texts. But for accessibility, an empty alternative text allows the images to be skipped by screen readers. An empty alt text is one of the ways to mark decorative images.
Often a clear and good alt text on a decorative image isn't that harmful from the accessibility perspective so a compromise in this might be an option. Consider your users and make the best content for them.
Pop-ups and overlays are often used to capture leads. But these can be problematic for accessibility if not implemented properly. While they might not be problematic for users if implemented correctly, the unfortunate truth is that the implementations do often have issues.