Indexability
Indexability checks whether search engines are allowed and able to index the page — covering canonical tags, meta robots directives, X-Robots-Tag headers, hreflang, and IndexNow support. Weight: 7.5%.
Details
Canonical tag
The canonical tag (<link rel='canonical' href='...'>) 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 <meta name='robots'> 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 <meta name='googlebot'> 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 <html> tag declares the page's primary language (e.g. <html lang='en'>). Missing HTML lang is a warning because it makes language detection harder for search engines and screen readers.
Hreflang
Hreflang tags (<link rel='alternate' hreflang='xx' href='...'>) 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 <meta> 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).
Metrics
| Metric | Description |
|---|---|
| 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 <html lang> 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. |
Related Topics
Technical SEO covers the infrastructure checks that allow search engines to find…
Architecture analyses the URL structure, HTTP response headers (caching, securit…
AI Readiness (AEO/GEO) measures how well the page is optimised for AI-powered se…
Run a free SEO audit to see how your site performs in this category.