Canonical tag
The canonical tag () tells search engines which version of a URL is the 'master' copy. If missing, Google must guess which duplicate to index. If pointing to a different URL, the current page may be deindexed in favour of the canonical target. The canonical URL must be absolute (include scheme and domain). A relative canonical is treated as invalid by most crawlers.
Meta robots
The tag controls crawler behaviour per page. Common directives: • noindex — prevents the page from appearing in search results (critical issue, −20 pts) • nofollow — tells crawlers not to follow links on this page • noarchive — prevents Google from showing a cached copy • nosnippet — prevents snippet display in SERPs A separate tag can override directives specifically for Google. All other meta robots issues are warnings.
X-Robots-Tag header
X-Robots-Tag is an HTTP response header that works the same as meta robots but applies to non-HTML resources (PDFs, images) as well. If both meta robots and X-Robots-Tag are present, the most restrictive directive wins. A noindex in the X-Robots-Tag header is a critical issue because it blocks the page from search results even if the HTML meta tag says 'index'.
HTML lang attribute
The lang attribute on the tag declares the page's primary language (e.g. ). Missing HTML lang is a warning because it makes language detection harder for search engines and screen readers.
Hreflang
Hreflang tags () tell Google which language/region versions of a page exist. They help Google serve the correct version in local search results. Common issues: missing x-default tag, missing self-referencing hreflang, and inconsistent reciprocal links between language versions.
IndexNow
IndexNow is a protocol supported by Bing, Yandex, and other search engines that allows sites to instantly notify crawlers when content is created, updated, or deleted. Instead of waiting for a crawl, the search engine fetches the page immediately. Setup requires placing a key in a tag and a verification file at the site root. Missing IndexNow is an info-level issue (−2 pts). If an IndexNow key is found but the verification file is not accessible, it is a warning (−10 pts).
Canonical URL — The canonical URL declared by the page, if any.
Canonical issues — Problems with canonical: missing, relative URL, or pointing elsewhere.
Is noindex — Whether a noindex directive is present (critical if true).
Is nofollow — Whether a nofollow directive is present.
Meta robots — Content of the meta robots tag (noindex, nofollow, etc.).
X-Robots-Tag — Content of the X-Robots-Tag HTTP header, if present.
HTML lang — The language declared in the attribute.
Indexable — Whether the page is allowed to be indexed (no noindex directive).
Hreflang count — Number of hreflang alternate language tags found.
Hreflang issues — Problems with hreflang: missing x-default, no self-reference.
IndexNow configured — Whether an IndexNow key is found (meta tag or plugin).
IndexNow key verified — Whether the key verification file is accessible.