Quick answer
Use a single meaningful <main> landmark for the page’s dominant content when the document has a normal content structure. It helps assistive-technology users navigate, but a missing landmark is an accessibility and structure review—not an automatic SEO failure.
What the issue means
A main landmark identifies the primary content area separately from navigation, headers, complementary content, and footers. In HTML, the semantic <main> element is usually the clearest implementation.
Why it matters for SEO
The main benefit is document clarity and accessibility. Better structure can support usability, but NOTABIS does not claim that adding <main> alone improves rankings.
How NOTABIS detects it
The missing-main-landmark rule checks for a literal <main> element in the measured HTML. It does not currently count role="main", even though that ARIA role can provide an equivalent landmark to assistive technology. It also does not perform a full accessibility audit or judge whether every landmark is correctly labelled. See the W3C main landmark example.
How to check it yourself
Inspect the delivered DOM for <main>. If the page uses role="main", note that it is semantically meaningful for accessibility but will still trigger this particular NOTABIS check. Test keyboard navigation and, where possible, use an accessibility tree or screen reader to confirm that the dominant content is discoverable.
How to fix it
Wrap the page’s primary content in one <main> element. Keep navigation, repeated headers, and side content outside it where appropriate. Avoid adding multiple competing main regions to silence a count-based finding.
For a typical content page, the main landmark can sit between the site header and footer:
<header>...</header>
<main>
<h1>Page topic</h1>
<p>The primary page content starts here.</p>
</main>
<footer>...</footer>
When this is intentional or does not need fixing
A fragment, embedded document, feed response, or non-HTML endpoint may not have a normal page landmark structure. Treat those separately from public content pages.
Related issues
Review H1 headings, duplicate main landmarks, empty headings, and unlabeled form controls.
Run a NOTABIS audit
Use the affected-page evidence to decide whether the missing landmark occurs on real content pages or on intentional utility responses.