Each one is a check that runs, described by the engine itself. If a check changes, this page changes with it.
HTTP status
http_statusThe status of the final response after redirects. Fails on anything outside the 2xx range, because a URL that does not answer 200 has no document to index; warns on a 2xx that is not 200. Reports not_measurable when the audit was run against supplied HTML rather than a live fetch.
Fixing it: Gives search engines a document to index at this URL at all.
robots.txt
robots_txtThe origin /robots.txt, parsed to RFC 9309: consecutive user-agent lines share a group, the most specific group wins, and the longest matching pattern decides with Allow winning ties. Fails when the audited path is disallowed for Googlebot; warns when the file is absent or declares no Sitemap. Distinct from the robots meta tag: a disallow here stops the crawl, not just the indexing.
Fixing it: Lets crawlers read the page, so every other signal on it can be seen.
Title tag
titlePresence, length and structure of <title>. Fails when absent or empty; warns outside 15-60 characters (Google truncates around 60) or when a separator-delimited segment such as the brand name is repeated within the same title.
Fixing it: Improves the strongest on-page relevance signal and the line people click.
Meta description
meta_descriptionPresence, uniqueness and length of <meta name="description">. Fails when absent or empty; warns outside 70-160 characters or when more than one description tag is present. Does not rank, but it is the copy that earns the click.
Fixing it: Raises click-through on the ranking you already have. Does not affect ranking itself.
Heading hierarchy
heading_hierarchyThe h1-h6 outline: how many h1 elements exist, whether any heading is empty, and whether the document skips a level (an h2 followed directly by an h4). Zero or multiple h1 elements and skipped levels both make the page outline ambiguous to crawlers and screen readers.
Fixing it: Gives crawlers and screen readers an unambiguous outline of what the page covers.
Business identity
business_identityThe business name as claimed in JSON-LD, og:site_name, the copyright line and the logo alt text, compared across those sources after normalising punctuation and legal suffix. Fails when a page that presents a business names it nowhere readable, or names it only outside structured data; warns when the sources disagree. Reports not_measurable on any page that does not present a business at all.
Fixing it: Gives search engines one stable business name to match this site against its own listings, reviews and citations.
Business contact details (NAP)
business_contactPhone numbers from schema telephone, tel: links and visible text, and addresses from PostalAddress, <address> and address-shaped copy. Fails on conflicting phone numbers, or on a business page with no contact details at all; warns when details exist but are not machine-readable or the structured address is incomplete. Reports not_measurable on any page that does not present a business.
Fixing it: Makes the phone number and address readable as data and consistent with the listings elsewhere that search engines reconcile them against.
Viewport meta tag
viewportPresence of <meta name="viewport">, whether it sets width=device-width, and whether it blocks pinch zoom via user-scalable=no or a maximum-scale below 2. A missing viewport fails mobile-first indexing; a zoom lock is an accessibility defect.
Fixing it: Makes the page usable on mobile, which is the index Google ranks from.
Image alt text
image_altShare of <img> elements with no alt attribute at all. An explicit alt="" is counted as a deliberate decorative marker, not a defect. More than 25% of images missing alt fails; a smaller share warns. Reports not_measurable when the page has no images.
Fixing it: Makes images usable by screen readers and eligible for image search.