Do you ever wonder how Google learns that a website exists online? Google isn't all-knowing and all-seeing (yet), so there must be something that enables it to know about new sites. After all, roughly 250,000 sites are created daily.
That “something” are the crawlers that work tirelessly to index every website and its pages. What are crawlers, and what is indexing? That's precisely what we'll discuss in this article, along with why they are highly beneficial for your website.
What's a web crawler?
Web crawlers are the hidden librarians of the internet, and they do a lot of work in the background that's not immediately obvious. It's through them that search engines learn about websites and can show them in search results.
A crawler is an automated program, a bot, that surfs the World Wide Web, gathers URLs and information about them, then hands it all off to a search engine for indexing. It's a logical, structured process that can be fully explained in a few steps.
The to-do list: Every crawl begins with a list of URLs. Some come from previous crawls, others from sitemaps submitted by owners, and the third are newly discovered links from other pages.
Selecting where to start: There are a few factors that determine which URL a crawl begins from.
URL importance (PageRank, backlinks, etc.).
Freshness or how often the page changes.
Crawl budget, which we'll explain in more detail below.
Crawler server load.
Robots.txt: Once a URL is selected, a crawler first checks whether it has a robots.txt and obeys its directives. They can include disallowing crawlers, blocking specific file paths, or implementing crawl delays.
Fetch the page: If the crawler is allowed to proceed by the robots.txt, it sends a request for the page's HTML structure, its headers, and a status code (whether the page is available, down, or missing).
Parse the HTML: Once the bot has the HTML, it parses it. It records text content, links, metadata (title, description, etc.), and structured data (JSON-LD and schema markup). After parsing everything, it checks for directives.
Noindex - stops the page from being indexed.
Nofollow - prevents a link from being followed.
Send links back to the to-do list: Every valid link is sent back to the list as a candidate to be crawled. Internal links help crawlers map your site, while external ones help find new sites.
Hand off to the search engine: Once the crawler has all the information it needs, it hands off the collected data to the search engine for indexing.
And that's how search engines learn about websites! They use automated workers that tirelessly and systematically browse the web. These crawlers gather valuable information that helps search engines understand a page's structure and content, and store it in a massive database. That's what indexing is.
The results we see on Google are simply the most relevant pieces of that stored information, shown to us based on what we searched for.
Why are crawlers beneficial for your site?
Trust us, we understand how it sounds: some bot, scanning your pages without your knowledge. However, it's better for your site in most cases. The only time you should be cautious is when you see bots you don't recognise, but more on that later.
All legitimate crawlers browse and index your site so that search engines can better "understand" your content. That comes with several significant upsides.
Discoverability: If your pages aren't crawled, the search engine has no way of knowing they exist, so it cannot serve them in search results. Crawlers add your pages to the search algorithm.
Organic traffic: Letting crawlers go through your site, you will not only see more organic traffic through search results, but the engine will understand your site's structure better. It will serve the most relevant pages to visitors.
Improved SEO: Search engines love a well-structured, fast site, and crawlers are how they notice such factors. Crawlers can evaluate your site, and the more user-friendly and quick it is, the better SEO visibility it will enjoy.
Fresh content surfaces more quickly: When you post a blog, update a product page, or make any content changes whatsoever, crawlers will revisit and refresh the search results. That helps your content stay relevant.
Discovering issues: Lastly, let's say you are using Google Search Console to monitor your site. If a crawler finds a broken link, duplicate content, missing metadata, or any other issues with crawling or indexing, it will let you know.
Crawlers can not only improve your site's organic traffic, SEO, and relevance, but also serve as an excellent diagnostic tool. Site health is just as important as good content and high traffic. So let's find out how to make it easier for crawlers to browse your site.
Best practices to make your site crawler-friendly
Now that we know crawlers are here to help websites garner more traffic, it's essential to understand how to make it easier for them. It does sound strange at first, making your site easier to browse by an automated program, doesn't it?
It all comes down to two things: crawl budget and ease of understanding. Let's explain.
Crawl budget: Crawlers can only crawl your site a limited number of times. They don't crawl constantly due to processing costs. After all, every crawl requires server resources. It's essential to optimize these limited attempts; the bot will visit your pages.
Ease of understanding: When we say that a crawler "understands" your pages, we don't mean it the same way a person does. Instead, it analyzes the content, looking for specific rules and signals: title, tags, headings, text, image, links, metadata, JavaScript (sometimes), etc. It uses its own version of machine learning to interpret the page.
By optimizing your site for crawlers, you help them understand your page's intent with fewer passes, which is what you want. There are several easy ways you can do this.
Use a clean HTML structure
What are almost all pages on the World Wide Web structured with? Yes, HTML. Because of that, crawlers love clean, logical HTML code that they can easily interpret.
It plays into what we mentioned above, about them "understanding" the page's content. Semantic elements like <header>, <main>, <article> and, <h1>-<h6> provide crucial context.
The bots can parse where the page starts, what its content represents, who it's aimed at, etc.
Finally, avoid using non-consecutive headings and too many <div> tags (the dreaded "div soup"). The former is self-explanatory. A jumbled heading hierarchy will confuse a crawler and make it harder to comprehend your content.
The latter, the <div> tags, don't provide any actual information to a crawler. <header> is a clear signal: this is where the page begins. <div>, on the other hand, is just a box with no context.
Keep your URL structure neat
The URL of a page is as much a part of the content as the content itself. People and crawlers can gain a lot of context from a URL when it's structured correctly.
That's why short, descriptive URLs are easier for bots and humans to understand. Avoid strings of random characters when possible. A good URL looks like this:
https://hosting.com/hosting/platforms/wordpress-hosting - The context is clear: web hosting for WordPress.
And avoid URLs like this:
https://example.com/product.php?id=3827&ref=xyQ9 - What is this? What's it about? Nobody knows.
In the same way your visitors appreciate clean URLs, so will the crawlers that visit your website. If you're setting up a new site, choosing the right domain name from the start makes a real difference.
Schema data and limited JS rendering
On the topic of "understanding" your website, schema data can help with that as well. Also known as structured data (JSON-LD), it provides context to crawlers about the thing they are looking at.
This data uses predefined vocabularies to define content elements such as "Person," "Product," "Recipe," etc. It's a machine-readable, standardized way of showing a crawler what a piece of content is about.
On the other hand, you have JavaScript that crawlers can render, but not reliably. Sometimes they don't render it fully, or skip it entirely. Because of that, if there are elements on your site you definitely want crawled, avoid JavaScript.
Optimize internal linking
We mentioned earlier that crawlers note down links within pages for later crawling. They can also follow them if they are done with the current page. That's why it's essential to link to important pages on your site often.
Internal links help bots discover the rest of your site and also understand it better. For best results, use descriptive anchor text ("Managed WordPress Hosting" and not "click here"). However, don't overdo it with internal linking.
Yes, we did say to link often, but there is such a thing as too much. How much depends on your page, so keep the links relevant (you don't want your text full of blue lines).
Upload an XML sitemap
Providing your favourite search engine with an XML sitemap is a great way to get the crawlers oriented. Uploading a map to Google, for example, will give the bots a head start on understanding your site structure and content.
There are many online tools you can use to generate an XML sitemap. Simply pick your favourite and check the documentation for the search engine you want to upload to for instructions. That's all you need to do; the crawlers will handle the rest.
The robots.txt file
The wise use of the robots.txt file can not only improve your site's crawlability but also keep away bots you don't want visiting.
As we mentioned earlier in this post, that file is what bots check before they begin browsing. It contains rules that specify which directories or files are off-limits, which bots are not welcome, and also where your sitemap is.
Here's a quick example of what those rules look like in practice. User-agent specifies the crawler a rule applies to, with the asterisk signifying "all."
# Allow major search engines
User-agent: Googlebot
Allow: /
# Block specific bots (example bad/unknown crawlers)
User-agent: MJ12bot
Disallow: /
# Rules for all other bots
User-agent: *
Disallow: /admin/
Disallow: /private/
# Block individual files
Disallow: /secret-notes.txt
# Allow assets (important for SEO)
Allow: /wp-content/uploads/
# Your XML sitemap
Sitemap: https://www.example.com/sitemap.xmlCrawlers are here to help
Web crawlers are the tireless, diligent workers that allow search engines to learn about your site. That way, they serve your content not only to the proper keyword search, but to the right people as well.
Your site risks obscurity and low organic search traffic if you omit crawling. They don't use any of your site's server resources, nor do they run complicated scripts that can slow it down. It's all done in the background for your benefit.
Allowing legitimate bots like Googlebot and Bingbot will have a tangible, positive impact on your site's discoverability and SEO. Letting them do their work will make it easier for you to attract more visitors.
Speaking of making things easier, if you're serious about improving your site's speed and performance, that'll make crawlers even happier. Fast sites get crawled more efficiently, which means your important pages get indexed quicker.
FAQ
What exactly is a web crawler?
A web crawler (also called a bot or spider) is an automated program used by search engines to browse the internet, discover pages, gather information, and send that data back for indexing. They help search engines understand your website and show it in search results.
How do crawlers find and index my website?
Crawlers start with a list of known URLs, follow links found on pages, check your robots.txt file, fetch your page's HTML, parse its content, and then send all of that data back to the search engine. The search engine then indexes your page so users can find it.
Why are crawlers important for SEO?
Without crawlers, search engines wouldn't know your site exists. Crawlers help with discoverability, improve organic traffic, evaluate site structure and performance, and ensure updated content appears in search results more quickly.
How can I make my site more crawler-friendly?
Use clean, semantic HTML, create simple and descriptive URLs, optimize internal linking, minimize heavy JavaScript, include structured data (schema), upload an XML sitemap, and configure your robots.txt correctly.
What is a crawl budget and why does it matter?
A crawl budget is the number of times a crawler will visit your site within a given period. Since crawlers can't crawl everything all the time, optimizing your site (clean code, good structure, fewer unnecessary pages) ensures they spend that limited budget on your most important pages.
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