If you want your website to show up in Google, you need to understand one thing first: search engines can’t rank what they can’t crawl.
Crawling is the starting point of organic visibility. Before a page can be indexed (stored in Google’s database) and later ranked, it has to be discovered, fetched, analysed, and processed.
In this guide, we’ll break down the stages of search engine crawling and show you what to optimise so Google can find and understand your most important pages efficiently. This blog will give you a solid overview of search engine crawling, which all boils down to technical SEO. To gain a more holistic view, we have a technical SEO guide that explains all the parameters in detail.
Search engine crawling is the process of discovering and downloading content from web pages using automated bots (also known as crawlers or spiders).
Google explains crawling as the way its systems discover and download text, images, and videos from pages on the internet. From there, the content can be processed for indexing and ranking later.
In simple terms:
Crawlers don’t behave like humans browsing a site.
They don’t read a page the same way you do. They request a page from a server, retrieve the code, and look for signals that help them understand:
Different search engines use different crawlers, and each crawler identifies itself using a user agent string.
This matters because if you accidentally block access (for example, with robots.txt rules), the crawler may never reach the content. If that happens, the page may never be indexed or ranked.
Here are a few common bots:
If your technical SEO foundations are clean, crawlers can get in, discover content quickly, and prioritise the right pages. Below is an image showcasing the current search engine market share according to seranking:
Search engines don’t just scan a site instantly. Crawling is a process made up of multiple steps, and each step can introduce issues that slow things down or stop pages from being indexed altogether.
Below are the five key stages.
Everything starts with URL discovery.
Search engines need to find out that a page exists before they can crawl it. They discover pages through signals such as:
A key point here: discovery doesn’t guarantee indexing. A URL can be found and crawled and still never appear in search results if Google decides it isn’t useful, accessible, or index-worthy.
Once the crawler chooses a URL to visit, it sends a request to the website’s server.
This is the fetching stage, where Googlebot (or another crawler) retrieves the page content.
Typically, the server responds with:
If the server struggles (slow response times, overload, errors), crawlers may reduce their crawl rate to avoid causing disruption.
After fetching the page, the crawler parses the HTML to extract useful information. According to H.Zhang parsing means analysing text or data to break it down into grammatical parts (like words, phrases, subjects, verbs) and understanding the relationships between them.
During parsing, crawlers typically pull out:
This is where crawling gets more technical.
Many modern websites rely heavily on JavaScript (JavaScript = programming language and core web technology) to display or load content. That means a crawler may need to render the page (similar to how a browser processes it) to fully understand what users see.
If key content is only available after JavaScript execution, and the render process fails or gets blocked, Google may struggle to see the full page.
Common issues that affect rendering:
Indexing is the stage where search engines store information about a page in their index so it can appear in results.
The index can contain signals such as:
Evidence: The core headline and supporting copy targets “SEO & AI Search agency” and “Specialist SEO Company”, which aligns with top-of-funnel + commercial intent.
Evidence: Clear navigation structure + short CTA blocks (typically good for responsive layout and scannability)
This information then feeds into ranking systems to decide when (and if) the page should show up for relevant searches.
These two terms get mixed up constantly, but they’re not the same thing.
Crawling = finding and retrieving content from a URL
Indexing = storing and organising the page content for search
A simple 1,2,3 breakdown:
So if you have pages that aren’t ranking, the real issue might be that they’re not even being crawled or indexed consistently.
If you want to improve organic performance, it helps to think about discovery and indexing like a pipeline.
To improve discovery, focus on:
You can also speed up discovery by manually submitting URLs through Google Search Console.
Once crawled, search engines look for signals that suggest a page is worth indexing, including:
Content quality and relevance (does it solve a real query?)
The page directly answers what the user searched for, clearly and completely.
Title tags, headings, and semantic structure
The page has a strong title in Google results, uses H1/H2/H3 headings properly, and is organised in a way search engines can understand.
Mobile-friendliness
The page works properly on phones (readable text, tappable buttons, no layout issues).
Page speed and stability
The page loads quickly and doesn’t jump around while loading (good user experience).
Structured data where relevant
Extra code (schema) that helps Google understand the content (like FAQs, reviews, products, events).
Clear internal links supporting topical relevance
Your pages link to each other in a logical way (blogs → service pages → related guides), helping Google understand your main topics and helping users navigate.
If you have thin pages, duplication, or a poor user experience, crawlers may still visit, but Google may decide not to index consistently.
If you want your pages crawled efficiently (and indexed consistently), keep the foundations simple:
If your site has solid technical foundations, search engines have fewer reasons to waste crawl time, which means your most valuable pages get priority. Check out how our friends at DR.Stretch did after coming in contact with the Hawks.
If you want help tightening up technical SEO and improving crawlability across your site, StudioHawk UK can help you identify crawl barriers, fix indexing issues, and build stronger performance from the ground up.