Although Google has provided us with the occasional breadcrumb over the years, we ultimately just don’t know how its algorithms really work. The majority of what we know about Google is based on observation. As reported by TechRadar Pro, this may soon change with the Digital Services Act, which goes into full force on Jan. 1, 2024.
Until then, educated guesswork is all we’ve got. Fortunately, that may be enough for at least a brief explanation of how Google’s algorithm indexes content. It also helps that this is one of the few areas where Google has been at least somewhat candid—knowing how to catch the attention of Google’s crawlers doesn’t confer the same sort of advantage as understanding how the search engine evaluates each and every ranking factor, after all.
So how does Google decide which content to index?
Per documentation published on Google Search Central, Google indexes pages through automated software bots known as crawlers alongside an algorithm it refers to as Googlebot. The company uses a nonspecific algorithmic process to determine which sites to crawl, how frequently to crawl them, and how many pages it should fetch from each site. Once it discovers a new site, Googlebot simulates page rendering using a recent version of Chrome.
To use an analogy, Googlebot essentially functions as a central overseer, monitoring the various nodes under its supervision for any changes using an army of digital drones. During this process, new pages may be discovered either through links to a known page or courtesy of web searches. Google further notes that Googlebot does not crawl every page it discovers, and that there are numerous factors that may cause its crawlers to overlook a page:
- The disallow flag, which indicates that a page should not be crawled.
- The noindex flag, which indicates that a page should not be indexed.
- A login process that renders the page inaccessible without authentication.
- Network problems.
- Server issues.
Although Google’s URL discovery is largely automated, there are two ways you as a website owner can trigger a manual crawl.
The first is to manually build and submit a sitemap to Google to help it crawl and index your page more efficiently. Google will only examine a sitemap the first time you upload it, or if you upload again to notify it of changes. Submitting a sitemap does not guarantee that it will be crawled immediately, and Google advises against repeatedly pinging or uploading the same sitemap.
Alternatively, you can use Google’s URL Inspection Tool through the Search Console to submit individual pages for crawling or recrawling. You can only do this if you are an owner or full user/administrator. There is a limit to the number of URLs you can upload at any given time, and each page should only be submitted once if unchanged.
There’s obviously a bit more to Google’s indexing process than we’ve described here. Unfortunately, we aren’t privy to those details, which Google keeps close to the chest. On the plus side, at least you now know a bit more about indexing, and specifically how it plays into your own SEO efforts.