Web crawling and scraping might sound the same, however, there are some key differences between both of the terms. Nevertheless, these two terms are closely intertwined. We know, does sound a bit all over the place, but don’t worry. In this article, we will go through their definitions, their differences, and how they accompany each other.
Scraping vs. crawling – the definitions
Before we get started, let’s get the definitions right of the different “scrapings” and “crawlings” that are thrown around on the internet, as well as the ones we will be using in this article.
Generally, there are two types of scraping. It can either be:
- Web scraping
- Data scraping
Same goes for crawling:
- Web crawling
- Data crawling
Now, the definitions of web and data are pretty clear, but to be on the safe side, web is anything found on the internet and data is information, statistics, and facts that can be found anywhere (not only the internet).
In our article, we will be going over what is web crawling vs. web scraping (keeping in mind that data crawling and data scraping in technicality is the same, except not performed on the web).
As our data analyst, Martynas Juravicius kindly informed us, there are a few ways web crawling and web scraping can be differentiated. So please note that we will be going over one of the ways they can be distinguished. Some of you may not agree with us – and don’t! Let us know in the comments below your thoughts on what you think are the main differences between web crawling and web scraping!
Now we got that out of our way, let’s jump into what we came here for.
What is web crawling?
Web crawling usually refers to collecting data from… you guessed it – the world wide web! Traditionally, done in big quantities, but not limited to small workloads. A crawler goes through (or crawls through like a spider) many different targets and clicks on them.
According to our python developer Bernardas Alisauskas, a crawler is “a program that connects web pages and downloads their contents.”
He explains that a crawler program simply goes online to look for two things:
- Data the user is searching for
- More targets to crawl
So if we tried to crawl a real website, the process would look something like this:
- The crawler goes to your predefined target – http://shop.com
- Discovers product pages
- Then finds and downloads product data (price, title, description etc.)
Regarding the last point, however (that one we conveniently bolded for you), we will exclude it from Bernardas notes and call it scraping.
Take a moment to check out his full article on web crawling. Bernardas really goes into detail how web crawling works and its different crawling stages, so if you’re interested in this from a tech side of things, go check his personal blog out.
What is web scraping?
If web crawling means going through and clicking on different targets, web scraping is the part where you take the found data and download it. Web scraping means you know what you want to take and then take it (e.g. in web crawling/scraping cases usually what can be scraped are product data, prices, titles, descriptions, etc.)
So as you might have gathered, web crawling usually goes together with scraping. When web crawling, you download readily available information online. And afterward, you filter out unnecessary information and pick only the one you require by scraping it.
However, web scraping can be done manually without the help of a crawler (especially if you need to gather a small amount of data), whereas a web crawler is usually accompanied by scraping, to filter out the unnecessary information.
Web crawling vs. scraping
So, scraping vs. crawling – let’s sort out all of the major differences between these two to see a clearer picture of both:
- Web scraping – only “scrapes” the data (takes the selected data and downloads it).
- Web crawling – only “crawls” the data (goes through the selected targets).
- Web scraping – can be done manually, by hand.
- Web crawling – can be done only with a crawling agent (a spider bot).
- Web scraping – deduplication is not always necessary as it can be done manually, hence in smaller scales.
- Web crawling – a lot of content online gets duplicated, and in order to not gather excess, duplicated information, a crawler will filter out such data.
Web scraping vs. web crawling differences are pretty clear – a crawler will crawl through various targets on the internet, like a spider crawls through its web. Once the crawler reaches the target, it gets scraped – the selected target’s data will be gathered and downloaded.
As we mentioned at the beginning of our article, this is only one of the ways to differentiate web crawling vs. scraping. Tell us what you think are the differences – or maybe there are none at all?
Also, if you are interested in testing out a crawler yourself, we offer to check out our Real-Time Crawler. You can test it out and see how it works – in essence, “it’s an advanced scraper customized for heavy-duty data retrieval operations.” Best of both worlds.
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