Web scraping and web crawling are often used interchangeably. However, while they share some similarities, these two processes are pretty much different. They should be approached from the web crawling vs web scraping perspective.
It’s completely understandable if it confuses you. Scraping and crawling use similar processes to complete the projects they are used for. On top of that, they also share some use cases. Below, you will find out what web scraping and crawling are and what makes them different.
Web crawling explained
There is a reason why web crawling is called that way. Crawling refers to the movement of a spider. It describes the irregular movement seen when a spider navigates its intricate web. Experts often use the term spider in jargon to refer to a web crawler.
A web crawler, or spider, if you prefer, is a program popularly called a bot. Crawler bots are programmed to crawl the world wide web. What is the purpose of this crawling? The objective is indexing. A crawler bot crawls the websites indexing the information found on its pages on autopilot.
Crawlers can access every bit of information found on a webpage and crawl deep into the website’s structure no matter how complex it is. They can be programmed to look for something specific such as a keyword, or set out on an ultimate quest – crawl every webpage online.
However, only on rare occasions do they look for all information online. This is the case with search engine crawlers, such as Google’s or Bing’s crawler.
Web scraping explained
Web scraping refers to the process of recording and storing information found online. This process is also automated, as is web crawling. But unlike web crawling, a web scraping bot scrapes the information or specific content from a website (can be text, image, video).
Web scraping bots don’t go around indexing everything on their way. They are often programmed to look for specific information or content and extract it once they find it. Web scraping bots usually have two targets. One target is defined by the location that hosts information. The second target is determined by what type of information a web scraper should extract.
While it may sound like a copy and paste job, in essence, it is not. Web crawlers extract the data immediately and store it without having to pause.
The differences between the two
Although they may seem similar, web scraping and crawling represent two different processes. Web crawling doesn’t have a data target. It can be set to search for web links in a list of URLs. The initial URLs are a crawler’s starting point.
The crawler will then go through all the pages on a website following the breadcrumbs, which are links to other pages. A crawler will click on every link available and index the information on webpages it goes through.
During the process, the crawler can take a snapshot of content that’s already there.
Web scraping, on the other hand, serves the purposes of data extraction. Websites have structured information such as product description, price, blog post, comments, business address, email, and phone number.
The goal of web scraping is to identify the data on a website, extract, and store it.
The main difference is that web crawling looks for any and all information, while web scraping retrieves precise data.
Unlike crawlers, scrapers can appear as human users. They can replicate human behavior on web pages, perform login and log out tasks, complete and submit forms, and identify themselves as a browser(s).
If you want to delve deeper into web crawling vs web scraping differences, we suggest you check out the Oxylabs website for more information.
Looking at the differences through use cases
Web scrapers can be used to extract any piece of information found on web sites. They have been recognized as valuable assets across verticals. Marketers use them to fetch contact details of businesses and individuals. They can extract data from business websites and social media platforms.
Scrapers are also used in the eCommerce vertical. Businesses use them to do market research and analysis, compare prices, or simply keep an eye on what’s the competition doing. While we are at it, scrapers are in use for competition monitoring and price comparison across other verticals, including real estate, medical services, automotive, and so on.
Since they can retrieve the data from multiple sources, scrapers are often used to feed data to Machine Learning algorithms.
Web crawlers are primarily used for downloading and indexing content from the World Wide Web. As we’ve mentioned earlier, they are mainly used by popular search engines. Their role is to index as many webpages as possible and make it easier for users to find the information they are looking for.
Hopefully, after reading our web crawling vs web scraping comparison, you’ve learned a thing or two about these two processes. As you can see, web crawling is a more general action aimed towards indexing content found online. In contrast, web scraping seeks to retrieve a specific piece of information from particular websites.