Web Crawling 101: All You Need To Know

Web crawlers, the lesser-known sidekicks of search engines, play a vital role in rounding up online content. Web crawlers are known by several names, including spiders, robots, and bots. These names describe what they do: they crawl the Internet to index pages for search engines.

Search engines don’t have any way of knowing what websites are available on the Internet. Before the systems can deliver the correct pages for keywords and phrases, or the words people use to locate a helpful website, they must crawl and index them.

What is Search Indexing?

Search indexing is similar to having a library card database for the Internet. A search engine knows where to look for information when a user types it in. It’s also equivalent to a book’s index, which lists all the places in the book where a specific subject or phrase is listed.

The text on the website and the metadata* about the page that users don’t see are the main focus of indexing. As most search engines index a website, they use all of the words on the page – except for “a,” “an,” and “the.” As users search for those words, the search engine scours its database of all the pages that contain those words and chooses the most important ones.

Metadata is data that informs search engines what a website is about in the sense of search indexing. Instead of visual material from the webpage, the meta title and meta summary are often on search engine results pages.

Why Are Web Crawlers Called Spiders, and How Do They "Crawl"?

The World Wide Web – where the “www” part of most website URLs come from – is another name for the Internet or the region that most users access. Since search engine bots crawl all over the Internet, much like real spiders crawl on spider webs, it was only natural to call them “spiders.”

This method could go on forever, given many web pages on the Internet that could be indexed for search. On the other hand, a web crawler will adhere to specific policies that allow it to be more selective about which pages to crawl, what order they should be crawled, and how frequently they should be crawled to search for content updates.

1. The Quality Of Each Website

Most web crawlers aren’t designed to crawl the entire publicly accessible Internet. Instead, they choose which pages to crawl first based on the number of other pages that connect to it, the number of visitors it receives, and other factors that indicate the page’s probability of containing necessary information.

2. Reviewing Sites

The content on the Internet is constantly being changed, deleted, or relocated. Web crawlers would need to revisit pages regularly to ensure that the most recent version of the material is indexed.

3. Robots.txt regulations

Web crawlers use the robots.txt protocol to determine which pages to crawl (also known as the robot’s exclusion protocol). They will search the robots.txt file hosted by the page’s web server before crawling it. A robots.txt file is a text file that defines any bots that attempt to access the hosted website or application. These rules specify the bots’ pages are allowed to crawl and the links they are permitted to obey.


Crawling every site on the Internet might be a challenging task, mainly if done manually. Web crawlers will assist you in achieving your goal of quickly obtaining knowledge. Of course, using The Social Proxy’s 4G proxies will make your crawling more safe, private, and dependable.