What does Google say about SEO? /
The Crawl & Indexing category compiles all official Google statements regarding how Googlebot discovers, crawls, and indexes web pages. These fundamental processes determine which pages from your website will be included in Google's index and potentially appear in search results. This section addresses critical technical mechanisms: crawl budget management to optimize allocated resources, strategic implementation of robots.txt files to control content access, noindex directives for page exclusion, XML sitemap configuration to enhance discoverability, along with JavaScript rendering challenges and canonical URL implementation. Google's official positions on these topics are essential for SEO professionals as they help avoid technical blocking issues, accelerate new content indexation, and prevent unintentional deindexing. Understanding Google's crawling and indexing processes forms the foundation of any effective search engine optimization strategy, directly impacting organic visibility and SERP performance. Whether troubleshooting indexation problems, optimizing crawl efficiency for large websites, or ensuring proper URL canonicalization, these official guidelines provide authoritative answers to complex technical SEO questions that shape modern web presence and discoverability.
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★★ Can the Mobile-Friendly Test really substitute the URL Inspection Tool for auditing mobile crawling?
The Mobile-Friendly Test always uses the mobile crawler and can serve as an alternative to test what the mobile Googlebot sees, especially for sites not yet migrated to mobile-first indexing where the...
Martin Splitt Apr 26, 2021
★★★ Can you really remove a noindex via JavaScript without risking de-indexation?
If the raw HTML contains noindex and JavaScript removes it, Google will never see this change because it will not render the page due to the initial noindex. Conversely, adding a noindex via JavaScrip...
Martin Splitt Apr 26, 2021
★★ Does Google really use different crawlers for its SEO testing tools?
The Mobile-Friendly Test systematically uses the mobile crawler by definition. The URL Inspection Tool uses the corresponding crawler (mobile or desktop) based on the site's mobile-first status. The R...
Martin Splitt Apr 26, 2021
★★★ Does a raw HTML noindex really prevent JavaScript rendering by Google?
If the raw HTML contains a noindex meta robots tag, Google will not render the page. Therefore, if JavaScript later removes this noindex in the rendered HTML, Google will never see it. The reverse wor...
Martin Splitt Apr 26, 2021
★★★ Does Googlebot Actually Collect Core Web Vitals Data During Crawling?
This week's update on Core Web Vitals... 🙂 John Mueller reminded us on Twitter that while the Googlebot returns a majority of useful information to the algorithm during its crawl, this won't be the ca...
John Mueller Apr 26, 2021
★★ Can an empty HTML canonical tag mistakenly force Google to auto-canonicalize your page?
An empty canonical tag in the initial HTML that is later filled by JavaScript can potentially cause unwanted auto-canonicalization. It's preferable to have no canonical tag at all than an empty one, o...
Martin Splitt Apr 26, 2021
★★★ How can a different canonical tag between raw HTML and rendered output destroy your canonicalization strategy?
Having a different canonical tag in raw HTML and rendered HTML sends conflicting signals to Google. This can weaken the canonical signal and lead Google to choose a completely different URL or alterna...
Martin Splitt Apr 26, 2021
★★ Can you really lose control of your canonical by leaving the href attribute empty at load time?
An empty canonical tag in the initial HTML that is then filled by JavaScript can cause involuntary auto-canonicalization of the page. It is better to either not include the tag at all or to create it ...
Martin Splitt Apr 26, 2021
★★★ Why does Google ignore your canonical tags when the raw HTML contradicts the rendered output?
Having a different canonical URL in the raw HTML and in the rendered HTML creates mixed signals for Google. This may lead Google to choose a completely different canonical or to alternate between the ...
Martin Splitt Apr 26, 2021
★★ Why does Google ignore your desktop structured data after switching to mobile-first indexing?
Once a site is migrated to mobile-first indexing, Google uses the structured data from the mobile version, even for the rich snippets displayed on desktop. During the transition period, both crawlers ...
Martin Splitt Apr 26, 2021
★★ Does Google really overlook your images during web search rendering?
Google does not necessarily fetch images during the rendering for main web search. Images are retrieved by Google Images, which has its own system. Google recognizes the existence of the image, its al...
Martin Splitt Apr 26, 2021
★★★ Are the structured data from your mobile version also applicable to desktop?
Once a site has migrated to mobile-first indexing, Google uses the structured data from the mobile version for all rich results, including those displayed on desktop. Before migration, the data from e...
Martin Splitt Apr 26, 2021
★★ Should you be worried about 'other error' issues with images in the Search Console?
In the URL inspection tool, 'other error' issues for images or resources like tracking pixels are normal. Google Search does not directly extract images (that's Google Images' job) and does not need t...
Martin Splitt Apr 26, 2021
★★★ Does Google really experience delays in discovering JavaScript links?
Links added via JavaScript after the HTML rendering are discovered a few hours later than those present in the raw HTML. Google first examines the raw HTML to discover links, and then after rendering....
Martin Splitt Apr 26, 2021
★★★ How can canonicalization ruin your visibility on long-tail queries?
If variant pages (e.g., products with different capacities) are canonicalized to a master page, only the canonical page will be indexed and ranked. If specific terms (e.g., 'blue iPhone') only appear ...
John Mueller Apr 23, 2021
★★ Should you really rewrite all your product listings to rank well?
Having unique product descriptions (different from those provided by the manufacturer) is a good practice that helps Google differentiate pages. However, it is not critical, especially if other aspect...
John Mueller Apr 23, 2021
★★ Why does Google crawl your image URLs without extensions twice before indexing them?
If Google cannot recognize that a URL points to an image (due to the absence of an extension), it will first attempt to crawl it for traditional web search, fail, and then potentially treat it as an i...
John Mueller Apr 23, 2021
★★★ Does a 301 redirect really suffice to impose the canonical to Google?
Google uses 301 redirects as a signal of canonicalization, but also relies on other signals: internal links, sitemaps, external links, and annotations. It can happen that a redirect is in place but th...
John Mueller Apr 23, 2021
★★★ Can A/B testing in JavaScript trigger a cloaking penalty from Google?
JavaScript-based A/B testing is acceptable as long as Googlebot gets a stable and consistent view of the pages. Changing colors, calls-to-action, and designs is acceptable. Significantly changing the ...
John Mueller Apr 23, 2021
★★★ Is it really possible to overlook the desktop version with mobile-first indexing?
With mobile-first indexing, Google uses the mobile version for ranking, but this does not mean that the desktop version can be neglected. The main content must be identical on both versions....
Google Apr 22, 2021
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