How Does Google Find Websites? A Deep Dive into Web Crawling

What is a bot?

Bot is a computer program that automatically performs certain tasks on the internet. The main reason for creating bots is to automate processes and improve their scalability. Work that would take an hour when done manually can take just 5 minutes when performed by bots.

How do Google bots work?

Web crawlers created by Google called Googlebot perform a process known as crawling. This is an activity that involves discovering new pages, or updating pages already known to the search engine.

Googlebot operates as a distributed system extracting different types of pages worldwide. Its architecture features specialized components for different content types:

Googlebot Desktop: Simulates desktop browser behavior
Googlebot Smartphone: Emulates mobile device interactions
Image Crawler: Processes visual content and alt text
Video Crawler: Analyzes multimedia files and transcripts
News Crawler: Focuses on time-sensitive journalistic content

Each variant of Googlebot is trying to accurately represent different ways of content access.

Google’s bot can be identified by its HTTP user-agent header and IP address, eg. Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)

How Google finds websites?

Search engines have many ways to find links. The most important is finding links to a site on other, previously indexed pages. Links leading to our site from outside (known as incoming links) are the most important ranking factor.

Internal and External Linking (Link Graph Analysis)

The most important way is following internal and external hyperlinks from known pages. This method is used mostly, especially for discovering new pages from the same domain. That’s why it’s super important to create internal linking structure.

And what’s even more important is getting external link, coming from already indexed website. And the more reputation website has, the more reputation our website can gain.

Sitemaps

Another popular method is searching through sitemaps. These maps are a list of URLs on the site that should be accessible from search engines. A sitemap also shows search engine bots how to crawl the site.

Sitemaps store information about a given link that’s important from a search engine perspective, such as the date of last modification, frequency of changes, or importance of the link. The sitemap should be located in the root directory.

Manual URL Submission

One of the way of directly inform Google about new URL is submitting manually specific URL through Google Search Console interfaces.

Which pages do bots not crawl?

By default, Google bots try to visit every page they encounter on the internet. However, if we don’t want a particular page to be visited or prefer to leave it unindexed, we must instruct Google bots ourselves about which pages they should not open and index.

robots.txt

One way to block bot traffic on a site is to create a robots.txt file. This file contains rules blocking or allowing access for specific robots to a given page. This file should be located in the root directory, similar to the sitemap.

Meta Robots Tags

Using meta tags placed in the head section of a webpage, we can control robot behaviors.

<head>
(...)
<meta name="robots" content="nofollow">
<meta name="googlebot" content="noindex">
(...) 
</head>

With these tags, we can issue the following directives to bots:

noindex – don’t index the page in search results
nofollow – don’t follow links located on this page
none – combination of both above
notranslate – don’t offer translations of the page
noimageindex – don’t index images found on this page
nosnippet – don’t show a text snippet of the page in results
unavailable_after: – don’t show the page in search results after a specified date

Crawling Frequency and Prioritization

How Google Decides When to Crawl Your Website

Google uses sophisticated algorithms to determine how frequently a website should be crawled. Not all websites receive equal attention from Googlebot, as crawling resources are allocated based on several key factors:

Site Authority and Reputation: domains with high-quality backlinks and consistent traffic receive more frequent crawls.
Update Frequency: Websites that publish new content regularly are crawled more often than static websites.
Crawl Budget Allocation: Every website is assigned a “crawl budget” - the number of pages Googlebot will crawl during a given time period. This budget depends on:
- Your site’s overall importance in Google’s index
- How quickly your server responds to Googlebot requests
- Whether crawling encounters errors or slow loading times
Content Freshness Requirements: Time-sensitive content (breaking news, event information) receives priority crawling.
Server Health Considerations: Googlebot automatically throttles its crawl rate if it detects your server struggling to respond.

Website owners can influence crawling through Google Search Console settings, however Google maintains final control over crawl prioritization to ensure efficient use of resources, and we have no way to force any Googlebot behavior.

The Indexing Process: How Google Processes and Organizes Web Content

After Googlebot completes the crawling process, the collected data undergoes several sophisticated processing stages:

Content Extraction and Analysis:
- Text parsing from HTML and metadata extraction
- Natural language processing to understand content meaning
- Entity recognition to identify people, places, organizations, and concepts
- Topic classification to determine subject matter categories
Quality Assessment:
- Evaluation of content against E-E-A-T principles (Experience, Expertise, Authoritativeness, Trustworthiness)
- Originality checks to detect duplicate or thin content
- User experience signals assessment (page layout, readability, mobile usability)
- Security scanning for malicious code or phishing patterns
Relationship Mapping:
- Building connections between related entities and concepts
- Establishing semantic relationships between pages
- Creating knowledge graph associations for factual information
- Analyzing citation patterns for academic or specialized content
Index Storage and Organization:
- Compressing and storing processed content in distributed databases
- Maintaining specialized indexes for different content types (web pages, images, videos, news)
- Creating inverted indexes that map keywords to documents
- Implementing efficient retrieval mechanisms for fast search response

The indexing system processes billions of pages daily, constantly updating existing entries and adding new content. This massive database enables Google to deliver relevant results in milliseconds without needing to access live websites during searches.

How Google Crawls Today’s Web

Currently used technologies are making it harder for search engines to crawl and index content. Google has adapted, but challenges remain. Let’s break down some key obstacles and how Google tackles them.

1. JavaScript-Heavy Websites

Many sites use JavaScript frameworks like React, Vue, or Angular, which load content dynamically. The problem? Search engines don’t always see this content right away.

How Google handles it: Google uses a two-step indexing process. First, it crawls the raw HTML. Later, it runs JavaScript using a headless Chrome browser to see the fully rendered page.

2. Dynamic Content Loading

Features like lazy loading, infinite scroll, and AJAX calls can hide content from search engines unless they interact with the page like a real user.

Google’s solution: Googlebot simulates scrolling and clicks to trigger hidden content and make sure it gets indexed.

3. Authentication Barriers

Content locked behind logins, paywalls, or other restrictions can’t be accessed by Googlebot.

Best practices: If you want some of this content indexed, consider structured data, public previews, or Google’s First Click Free policy.

4. Mobile-First Indexing

Many sites display different content on mobile versus desktop, which can create inconsistencies in search rankings.

What Google does: It prioritizes the mobile version of your site for indexing, so make sure your mobile site has the same key content as your desktop version.

5. Rich Media Content

Videos, interactive elements, and non-text content can be difficult to understand without additional context.

Google’s approach: It relies on metadata, transcripts, alt text, and surrounding content to interpret rich media.

The Future of Web Crawling

Technology is evolving fast, and web crawling is no exception. Here’s where things are headed:

AI-Driven Crawling

Search engines are getting smarter with AI. Future crawlers might:

Predict which pages are worth crawling before even visiting them.
Learn from user engagement to refine crawl priorities.
Use natural language processing (NLP) for deeper content understanding.

Real-Time Indexing

Instead of waiting for crawlers, sites may push updates instantly to search engines. This could mean:

Faster indexing for news and time-sensitive content.
APIs that let website owners submit updates directly.
Search results that refresh in minutes instead of days.

Multimodal Search

Search is expanding beyond text. Future crawlers will:

Analyze images, videos, and audio alongside text.
Connect related content across different formats.
Improve voice and visual search capabilities.

Sustainable Crawling

Crawling the web takes energy. Search engines may focus on:

More efficient algorithms to reduce processing power.
Scheduling crawls based on energy availability (e.g., during low-carbon grid hours).
Prioritizing high-value content to minimize unnecessary crawling.

What This Means for Website Owners

To stay ahead, consider:

Using structured data to help search engines understand your content.
Implementing instant indexing for fast updates.
Optimizing for multimodal search (images, video, voice).
Keeping privacy regulations in mind when designing your site.

Search engines are getting smarter, but so are the challenges they face. By understanding these trends, you can make sure your content stays visible and relevant in the evolving web landscape.

Conclusion: Building Bot-Friendly Websites for Maximum Visibility

Understanding how bots work and interact with your website is crucial for successful SEO. By following best practices for crawlability, you can create a website that search engines love to index.

Quality of content and good UX are the most important factors, not only for Google but also for your users.

Kamil Kwapisz