How website crawling works

Crawling is how search engines discover and index web pages. In other words, it is how search engines ‘know’ what web pages exist, so they can display the most relevant answers in SERPs when someone searches for particular information. This term is broad, and can also be used when referring to crawl “budget”, crawl “depth”, crawl “error” and more.

Essentially, it all comes down to the processing of a particular URL. Crawling happens when a website is searched (crawled) by a bot/s. These bots analyze the code and content on a specific page, and gather information about the intent of your content. Crawlers (or bots) will also view internal and external links during the collection process, and index these pages.

While Google allocates crawl budgets to every URL, the amount you get is determined by a handful of things: the importance of a webpage according to its trust signals, the page’s link structure, etc.

Types of Crawling

Google performs two types of crawling:

• Discovery: To find new content on your website
• Refresh: To find updated information in already-indexed content

Why Is Crawling Important for SEO?

Crawling ensures that people can find your website’s content in search results — which sets the premise for earning organic traffic and ranking high in the SERPs. In other words, without being crawled, your website cannot be indexed properly, meaning your content cannot rank well (if at all). So, crawling is the first step to even appearing online.

Crawling also helps search engines provide relevant search results for specific queries — improving SERP quality.

As search bots scan different web pages, they recognize the meaning and context behind the content. With these details, search engines can provide results that match search intent for different keywords or phrases.

Crawling also allows search engines to track changes to websites, such as new content, permissions, redirects, and metadata. With this data, search engines quickly adjust the SERPs to reflect up-to-date information on different web pages. It ensures that users find the most accurate and up-to-date information for different queries.

How Do Search Engines Crawl Websites?

First, the crawlers download your website’s robot.txt file. The robot.txt file contains information about which web pages should or should not be crawled on your site.

Next, the crawlers fetch a few pages from your website and follow the internal links on these pages to discover other content. The crawlers add all of the discovered content to their database, where they can retrieve relevant URLs whenever someone searches for specific information.

How to Optimize Your Website for Crawling

There are several ways to ensure search engine bots crawl your website.

1. Ensure That Your Website Has a Well-Constructed and Updated Sitemap

An XML sitemap is like a directory with information about the different content pages on your website. It helps search engines quickly find and crawl the pages on your website. As you make updates to your website, re-submit your sitemap to the search engines for indexing.

2. Make Your Content Visible to Crawl Bots

Any content that is blocked by no-index tags, robots.txt files, or other protective measures won’t be crawled. Ensure that the search engine bots can view all the content assets in your web pages — images, videos, GIFs, and the like.

3. Focus On Page Speed and Technical Optimization.

The faster your website loads, the faster search engines can crawl and index its content.

• Use pre-rendering tools to improve your page load speed
• Optimize your images for mobile search
• Fix and redirect broken links
• Set up a URL structure for your website

4. Fix Your Site’s On Page SEO

Optimize your web pages for relevant keywords. This helps search bots understand and classify your content correctly, which in turn, improves your SEO rankings.

For example, this page is about crawling, so we’ll optimize it for keywords like:

• What is crawling in SEO?
• How to crawl a website
• Web Crawling Add these keywords to your meta titles, descriptions, headings, body copy, and other on-page elements naturally — don’t stuff them in. And by stuff, we mean insert for the sake of it. Any keyword insert should be seamless as Google analyzes the words before and after the keyword to understand the full context of copy.

Crawling SEO FAQs

Find answers to your most common web crawling questions.

What is a Crawl Budget?

A crawl budget is the number of web pages search engine bots can effectively crawl at a given time. It differs from one website to another.

Is Crawling a Ranking Factor?

No. Crawling does not directly impact how high your web pages rank in search results. However, your content must get crawled and indexed to appear in search results in the first place.

Crawling vs. Indexing

Crawling is when search engine bots scan your website to discover new pages or changes to existing pages. On the other hand, indexing means organizing crawled content based on keywords and context. It helps search engines display relevant results for different keywords.

What is a Crawler?

A crawler is a search bot that automatically scans websites for new and updated content pages. Google’s web crawler is called The GoogleBot.

Can I Ask Google to Crawl my Site?

Yes, you can manually submit your site’s URL for Google to crawl and index in two ways:

• Submit your updated sitemap to Google via Search Console
• Use the URL inspection tool to submit a specific page URL for indexing