What is Web Crawler?

We used web crawler term since crawler is a technical term for automatically accessing the website and acquiring data via software program. Brian Pinkerton was the first person who started working on web crawler, with the help of web crawler he created a list of top 25 websites on his desktop since originally it was a desktop application.

It is a program that is used to automatically index website content and other additional information over the internet, these types of programs are designed in such a way so that they can create entries on search engines index.

It systematically browses the website and grasps what each page of the website is about, so that all this information can be indexed , updated and retrieved by a web crawler whenever any user makes a search query.

There is a reason whenever any user browses about any website and it ranks top on search engines because it is indexed by web crawlers that’s why search engines can find them organically.

How Does Web Crawler Works?

Web crawlers discover new pages , index them, and then store them for future use. The purpose of web crawler is to crawl your content at a specific interval so that your search results get updated with time and searchable.

They start from a list of URLs called a seed. This seed sends the crawler to specific web pages, where the process begins. One of the great things about web pages nowadays is that they have hyperlinks, which the crawlers will follow. And then follow the hyperlinks on the consequent pages, and so on.

Web crawlers follow a few rules that dictate which pages get indexed and which ones are left for later.

1. Page Importance:

Web crawlers try to index those pages that contain valuable information, regardless of the topic. They analyze whether a page has such information based on several factors: the number of backlinks and internal and outbound links, traffic, and domain and page authority.It is the foundational rule of web crawlers and has the highest impact on page crawling.

2. Robots.txt.rules:

If we talk about robots.txt file it is a file as well as a protocol.This file is on the website’s hosting server and it has access rules for the bots themselves. Before crawling a website, the bots will checkout for a robots.txt file, and if any one is present, they will see its rules. If any forbid crawling, the bot will not index the page and move on. The file is quite helpful to prevent bots from crawling your pages or want only specific bots to have access.

3. Re-Crawling Frequency:

Pages on the internet are updated constantly and nonstop, which means they have to get re-crawled and re-indexed. But a bot can’t just sit on a page and wait for it to get new content so it can do those things. Because of that, each search engine has its own frequency for returning to pages to look for new content. For instance, Google does it between once a week and once a month, depending on the page’s importance. You can also manually request a crawl from Google by simply following their guide here. More popular pages get re-crawled more often.