Crawling in SEO is the automated process where search engine bots (like Googlebot) browse the web, following links from page to page to discover new, updated, or existing content.
In a more technical point of view, Googlebot finds URLs through links and sitemaps, visits those pages to retrieve their content, and then sends the information back to Google so it can be processed and indexed. If a page cannot be discovered or accessed during this process, Google cannot evaluate or rank it in search results.
What Crawling Means In Google Search
When people talk about ranking in Google, they often jump straight to keywords. In practice, none of that matters if Google cannot crawl your website first.
Crawling is the process where Google discovers and fetches web pages using automated programs known as crawlers. These crawlers scan the web and retrieve pages so Google can understand what exists on the internet.
The crawler used for Google Search is called Googlebot. It visits URLs, downloads the page content, and passes the information to Google’s systems for further processing.
From my experience working with websites, crawling is often overlooked. Many businesses assume that once a page is published, Google will automatically find it. That is not always the case. If Googlebot cannot discover or access a page properly, the page might never appear in search results.
Small Businesses Are Often Ignored by Google’s Algorithm
Amongst experienced SEO marketers, it is common knowledge that Google’s search algorithms and ranking systems frequently exhibit a preference for established brands, often prioritising them over smaller, less-known competitors.
As a result, small businesses in Singapore should manually request indexing for new pages in Google Search Console to prompt Googlebot to crawl them sooner.
What Googlebot Actually Does When It Visits A Page
Googlebot behaves like a simplified web browser. When it reaches a page, it performs a few key actions:
- Googlebot fetches the HTML content of the page.
- Googlebot extracts links from the page. It then sends the page data back to Google’s processing systems.
Google uses a large distributed system to crawl billions of pages across the web. The crawling process is algorithmic, meaning Google decides which sites to crawl, how often to revisit them, and how many pages to fetch.
This explains why some pages get crawled quickly while others take weeks.
For example, when I publish an article on a website with a strong backlink portfolio, Googlebot may crawl it within hours. On a brand new website with no links, Google may take longer to discover the same page.
How Google Discovers New Pages
Google does not crawl the internet randomly. It relies on URL discovery. From an SEO perspective, these are the most common discovery methods.
Internal Links
Links are the primary way Google discovers new pages. Googlebot follows links from already known pages to discover additional URLs.
This is why internal linking is extremely important. If a page is not linked anywhere on a site, Googlebot may not find it.
XML Sitemaps
A sitemap provides a structured list of URLs on a website. It helps Google discover pages more efficiently, especially on large sites.
In practice, I treat sitemaps as discovery hints rather than guarantees. Submitting a sitemap does not mean Google will crawl every URL.
External Links
Links from other websites also introduce new URLs to Google.
This is why backlinks and brand mentions sometimes lead to faster crawling of new pages.
The Different Types Of Google Crawlers for Search
Google operates several crawlers for different products. According to Google’s crawler documentation, automated programs used by Google fall into different categories including crawlers and fetchers.
For Google Search, the main crawler is Googlebot, which has two primary variants.
Googlebot Smartphone
This crawler simulates a mobile device.
Google now uses mobile-first indexing, meaning the mobile version of a site is used for indexing and ranking.
Googlebot Desktop
This crawler simulates a desktop browser.
Although both exist, most SEO analysis today focuses on the smartphone crawler because Google primarily evaluates the mobile version of pages.
Google also runs specialised crawlers for images, videos, and other search features.
What Happens After Crawling
Crawling is only the first stage of Google’s search process.
After a page is crawled, it moves through 2 additional steps:
- Rendering
- Indexing
For websites that rely on JavaScript, Google first crawls the HTML and then renders the page to execute scripts before indexing the content.
This is why JavaScript-heavy websites sometimes face SEO issues. If rendering fails or resources are blocked, Google may not see the final content.
From a technical SEO standpoint, I always check how Google renders pages in testing tools. What developers see in the browser is not always what Googlebot sees.
How Google Decides What To Crawl
One useful clarification from Google’s latest documentation about crawling is that Google schedules crawling through internal systems.
Google maintains queues of URLs that need to be crawled and continuously prioritises them.
According to the latest documentation, the system determines which pages should be crawled again based on factors such as site changes, popularity, and available crawling resources.
In simple terms, Google does not crawl every page equally.
Pages that change frequently or attract strong signals may be crawled more often, while less active pages may be revisited less frequently.
Technical Factors That Affect Crawling
In my experience auditing websites, several technical factors can quietly prevent Googlebot from crawling pages.
Robots.txt
The robots.txt file controls which sections of a site crawlers can access.
If a directory is disallowed, Googlebot will not crawl those URLs.
However, blocking crawling does not always stop a URL from appearing in search results if other pages link to it.
Noindex
If a page should not appear in search results, the correct method is the noindex directive.
This can be added through a meta tag or HTTP header.
Server Performance
Googlebot typically does not request pages from a site more than once every few seconds on average.
If a website server responds slowly or frequently returns errors, Google may reduce its crawling activity.
URL Structure
Clean and logical URL structures help Google crawl a website more efficiently.
Poorly structured URLs can lead to inefficient crawling or important pages being overlooked.
Crawling Issues Cannot Be Ignored
From my experience, crawling issues are one of the most common reasons pages fail to rank.
A page cannot be indexed if it is never crawled. And it cannot rank if it is not indexed.
Many technical SEO tasks revolve around making crawling easier:
- ensuring pages are discoverable through links
- maintaining a clear site structure
- avoiding accidental crawl blocks helping Google understand which pages matter
Once crawling works properly, other ranking factors such as content quality and backlinks can start to have an effect. Without crawling, the rest of SEO cannot happen.
