If you are familiar with search engines and big data, you’ve probably stumbled upon web scraper and crawler terms. These terms are commonly used in articles that address big data business and individual use cases.
While many people use these terms interchangeably, you shouldn’t make this common mistake. These two are entirely different. The best way to understand the differences is to discover what scrapers and crawlers are.
What are web scraping and crawling?
Before diving deeper into the differences between a web scraper and a web crawler, let’s quickly see what each of these stands for.
A web scraper is a script used in web scraping operations. Although it might sound like something complicated, web scraping really isn’t. It refers to extracting data from online sources such as web pages. Web scraping extracts data and stores it into one file. That file can be anything ranging from JSON to a simple excel spreadsheet.
Since it’s tedious to copy-paste data from hundreds of web pages, developers have come up with a web scraper. It’s a tool that completely automates the entire web scraping process. You can build custom scrappers and configure them to extract only the specific data from a target website.
While web crawlers are used in some data extraction projects, they are somewhat different from web crawlers. A web crawler is a script that goes through all web pages of the target website(s). That’s why the web crawling process is also called indexing, something that all major search engines do.
A web crawler will go through the entire website and index all its pages, storing all the information it finds on the pages. Besides search engines, web crawlers are also quite commonly used by online aggregators and statistical agencies.
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Scraper vs. Crawler: key differences
You can already start guessing the main differences between scraping and crawling. Let’s break it down and see what makes these two unique.
Both web scrapers and crawlers can be customized, but not to the same extent. A crawler will generally pull all the data from a website unless you specify that you only want to extract the HTML website structure.
With web scraping, you have more freedom. You can target specific web pages on target websites. Plus, you can choose which data you want to extract with surgical precision.
Scope of data extraction
As mentioned, web crawling usually extracts all the data from the target sites. It’s a broad-scope operation, which is why only niche companies do it.
Web scraping, on the other hand, provides you with usable data. Since you are extracting only specific data from a website, it’s a much smaller operation than web crawling in terms of scale.
Finally, the output of the web crawling process is this massive file of raw data or simply a list of all the URLs of a website. The output of web scraping operation is a ready-to-read or use spreadsheet or data file. It can contain dozens of data fields you can inject into a data analytics tool to generate insights, charts, or run forecasting.
Most common scraper and crawler use cases
With everything we’ve covered so far, it’s logical to see that web crawling and scraping have found entirely different use cases.
Let’s start with web crawlers. You will see search engines like Google and Bing using crawlers daily. It enables them to keep their databases updated and streamline searches for their users.
Crawlers are great for this because they go through entire sites and can extract all data. Without web crawling, search engines wouldn’t be able to return the pages that contain the information you are searching for.
Crawlers are also commonly found in tech stacks of statistical agencies and massive site aggregators. For instance, bed banks use them to source all available accommodations and list them on the main aggregator site.
When it comes to web scrapers, they found many business use cases. Companies use them for market analysis and to get data they can use to develop attractive pricing strategies. They also use it to identify keywords the competition is using so they can rank better. Web scraping also enables companies to improve brand protection as it helps them identify all brand mentions online.
Although similar, these two terms stand for two completely different scripts. Crawlers can only go through the structure of a website, while you can customize a web scraper to pull and return precise data from a website. That’s why businesses most commonly use them to streamline customer sentiment analysis, adopt dynamic pricing strategies, and do market research on demand.