| Crawler accessibility | The robots file, header and page directives, accidental resource blocking | One wrong rule can remove entire sections from the index with no visible warning |
| Index status | Pages submitted against pages indexed, the reason for each exclusion | "Discovered, currently not indexed" means something different from "Duplicate". The treatment differs completely |
| Canonical address | Self reference, conflicts between canonical, redirect and sitemap | Contradictory signals make Google choose for itself, often a different page from the one you wanted |
| Duplication | Variants with and without trailing slash, with parameters, pagination, filters, tag archives | Three addresses for the same content split authority instead of accumulating it |
| Redirects | Chains, loops, temporary redirects left over from old migrations | Every hop costs time and dilutes the signal passed along |
| Heading hierarchy | A single main heading, correct subordination, no skipped levels | Structure is how both Google and an AI assistant understand what the page is about |
| Titles and descriptions | Uniqueness, length, search intent, click through rate in Search Console | Third position with a good title brings more traffic than second position with a weak one |
| Structured data | Validity, matching what is visible on the page, the types relevant to your field | Valid markup unlocks rich results. Markup contradicting the page attracts manual penalties |
| Internal links | The depth of every page, orphan pages, anchor text, authority distribution | A page no internal link points to tells Google it does not matter |
| Sitemap | Completeness, accuracy of modification dates, absence of addresses that should not be included | A sitemap containing redirects and 404s reduces your crawl credibility |
| International signals | Declared language, diacritics, region markup if you have multiple versions | It determines which market and which language you are considered relevant for |
| Images and media | Alternative text, filenames, dimensions, presence in the sitemap | Image search is a channel almost everyone in the local market ignores |
| Web vitals | The same measurements as the performance module, but read as a ranking factor | On mobile, page experience separates otherwise equivalent results |