What is Web Crawling: A Beginner’s Guide

What is Web Crawling: A Beginner’s Guide
The Siliconreview
30 November, 2020


Although web crawling is unknown to most users of the internet, a lot of websites make use of this process (also referred to as "Spidering") as a means of the provision of up to date data. The process is becoming more accessible as businesses begin to utilize third party online data extractors (e.g. a Google scraper) for profit-driven purposes.

Web crawling is certainly a technical process but it can be simplified to a more bite-sized procedure, which is exactly what will be done in this article. So if you want to know the basics of web crawling, its function, process,  and use cases, keep on reading.

What is web crawling?

Web crawling is a process whereby automated programs called 'bots', 'crawlers' or 'web spiders' are utilized to methodically browse the web with the sole purpose of indexing web pages and whatever content they may contain. The term "web crawling" depicts the process of crawling which is the technical term for accessing a website automatically and obtaining data via a software program.

These bots, in a nutshell, perform the function of a librarian who organizes the books in a library according to categories using a card catalog for easy access by users. It is almost exclusively used by search engines to properly index these web pages so that they'll be easier to find or locate.

Why crawl a website?

There is usually a wrong assumption made by people, thinking that all you need to be discovered on search engines like Bing, Yahoo, or Google is to create a website and post content. This is as far from the truth as possible, your website has to be in the search engine's archives to be searchable, meaning it has to be indexed.

To be indexed, your website has to be crawled, this is why along with other specific algorithms, your site must be crawled to determine if it will be indexed or not.

How does it work?

Search engine bots crawl websites by navigating through their links on each page, these are links that connect each page to another on the same website. For new websites that do not have linked pages yet, you can request that your website be crawled by the submission of your website URL on Google Search Console. Crawlers are always "Crawling" the web for new websites, they are like the Spanish explorers looking for new land and territories.

They search for new and discoverable links on pages and once they gain an understanding of the website's features, they note them down on their Map for future use. Website crawlers can only access public pages to collect data, while private pages are referred to as the dark web. Below is a rundown of how web spiders work according to specific policies and protocols;

Step 1: Web crawlers are provided a URL

Step 2: They then skim through the website, assessing its features and content

Step 3: The data collected is then stored in a massive archive unique to the search engine-referred to as the index

Step 4: After indexing, these bots navigate links to other pages and repeat the process

How do web crawlers affect SEO?

SEO is the goal of indexing and crawling, Search Engine Optimization is a procedure which involves preparing content for search indexing to ensure that it shows up higher in search results. Without web crawlers (e.g. Googlebot) getting access to your website pages and indexing them, your website cannot be Search engine optimized, this is why you shouldn't block web crawlers bots from your website if you want organic traffic coming to your website.

What are custom web crawlers?

Nowadays, having a web crawler (or scraper) isn’t just for giant businesses like Google. Smaller companies have developed tools that can acquire data from nearly any website on the web and deliver it to interested parties. Users simply send queries to endpoints (in a similar manner like any search engine) and the providers retrieve the data.

Businesses utilize web crawling to create big data databases. Data is then analyzed to gain a competitive advantage over others. Some businesses scrape e-commerce sites to get pricing intelligence, others utilize a Google scraper to gain insights into search engine rankings.


Although there are some bad bots out there, web crawlers are very necessary tools for good discovery rates, search engine optimization, and business data. Businesses of all types utilize web crawling tools - from tech giants like Google that rely on their bot to build the search engine to small digital marketing agencies that try to reverse engineer search algorithms to deliver better services to clients.