Web Crawling vs Web Scraping: What’s the Difference?
Web scraping and web crawling are two terms you may have heard used interchangeably — but they’re not the same thing. One has to do with indexing pages in search, while the other deals with retrieving data from those pages.
If you’re looking to use web scraping to gather data for your business, it’s especially important to know the nuances of these terms. Both are important to boost your business online, although they work in different ways.
Here we’ll define web crawling and web scraping, go over the differences between them and tell you how you can get started web scraping for yourself. If you’re looking for specific information, use the table of contents to jump to a section.
What’s Web Crawling?
Any research into search engine optimization (SEO) for online businesses will turn up the term “web crawling.” Web crawling is the process of reading and storing the data from a website for the purpose of cataloging it.
Google search is probably the most well-known example of this in action. Whenever you type something into the search bar, Google crawls the web for the most relevant information related to that search. Google uses bots, aptly called web crawlers, that are designed to read and index the content of a website to return those results.
Indexing pages via web crawling allows search engines to return results much more quickly. Since the information has already been stored under a certain category, it’s easily retrieved when someone runs a search.
Web crawler bots generally do one of two things on the internet:
- Search the web for more targets to crawl
- Look for search information that someone has requested
When you run a search and a crawler bot becomes active, the process it goes through to get your results is usually the same three broad steps. Say you search for sandals, for example:
- The crawler goes to the target website address or URL.
- It reads the site to find where the product pages are.
- It finds the product data (price, description, title, and so on).
You then get a list of results telling you where to buy sandals.
When a crawler downloads that information to index and store it for later searches, that’s where web crawling and web scraping work together. By downloading the data from that page, the crawler bot is performing web scraping.
Many of the measures you take to boost your website’s SEO are to make it easier for crawlers to access. Keywords, headings, backlinks, and the like all tell the crawler that your website contains relevant data to a person’s search.
What’s Web Scraping?
Web scraping is the act of extracting any publicly available data from a website — usually at a large scale — and storing it in a different file format. That file format is usually Excel, XML, or SQL so the data can be easily organized and read later on.
Web scraping can be done manually by one person — if you’ve ever copied and pasted information from a website to save for yourself, you’ve done a kind of web scraping. It doesn’t make sense to do that for hundreds of web pages to gather data at a large volume, however.
To solve that problem, large-scale web scraping projects are automated and often use custom-built bots programmed to find specific information. For example, if you sell watches and want to get an idea of how your competitors are pricing their product, you could design a bot to scrape just the price data from their websites.
The web scraping process usually has four parts:
- Send a request to the target website.
- Get a response from the target.
- Parse and extract that response.
- Download the data.
Web scraping uses a web scraper bot to do the job. If you have the coding knowledge, you can write one yourself. Or you can buy a high-quality scraping bot that’s ready to go out of the box.
Whereas web crawling involves reading every page of a website to gather all its data for indexing, web scraping doesn’t necessarily require the same thing. When web scraping, you’re only focused on a specific set of data, so the bot only needs to visit those areas of the target website where that data lives.
Web Crawling and Web Scraping: The Differences
If web crawling and web scraping are so similar, then what are the differences between the two? The short answer is that crawling has more to do with finding and categorizing, whereas scraping has more to do with downloading specific data.
You can scrape data manually by copying and pasting without the help of a crawler. By contrast, web crawling has to make use of data scraping to filter out unnecessary information. It usually requires a crawler bot.
Web crawling generally involves going through every single page of a website and following all the links to read and catalog the data for the entire site. Web scraping usually only focuses on a specific set of data — like prices, social stats, etc. — then retrieves and downloads just that data.
To sum up, there are three main areas where web scraping and web crawling differ:
- Operation: This is how web crawlers vs web scrapers “move”.
- Function: This is what web crawlers and web scrapers do.
- Deduplication: This is whether duplicate information gets removed as part of the process.
Web crawlers are designed with the purpose of cataloging and indexing. That core function affects how they operate. They find, read, and store data from web pages to be used later. They go through every page on a website. Google’s web crawlers are a prime example of this.
Web scrapers — whether self-written or pre-built — are designed to hunt down, retrieve, and download a specific set of data. They then export that data in an easily organizable format like Excel or XML. They do not visit every page on a website, and the data they retrieve will depend on the parameters written into their code.
Web crawlers will remove duplicate information as part of the process. They’re programmed to find the most relevant information. Duplicate information gives crawlers more to gather, so they’re programmed to get rid of it and sift through what’s left to find the best result.
Web scrapers don’t necessarily remove duplicate information, though some higher-end programs can be made to do it. If you’re web scraping at a very large scale — as is the case for a lot of businesses — it makes sense to invest in a program that can remove duplicates.
How Businesses Can Use Web Scraping
Web scraping is a highly useful tool that many businesses regularly take advantage of. As long as the data you need is publicly available, you can scrape and analyze it for a variety of purposes. Those include:
- Sales and marketing data: Web scraping can help generate new leads by finding people who are already likely to be interested in your product. It can also give you insights into how well your ads are performing. You can even tell what people are thinking of your business by scraping the review data from major websites.
- Analyzing the competition: Data from competitor’s websites can tell you what their pricing strategy is, how effectively they’re marketing their products, and more.
- Ecommerce product development: Scraping data like product descriptions from e-commerce websites can reveal what product descriptions are doing well regarding SEO. You can also study a competitor’s brand voice when reading how they write their descriptions.
- Public relations: Web scraping can be used to keep an eye on your online brand mentions. News articles, social mentions, and more can be retrieved and analyzed to gauge customer sentiment and see if any issues are developing that you need to get ahead of or investigate.
- And more: You can use web scraping for anything that lends itself to data analysis.
Some truly valuable insights are available to you if you get creative with data collection.
What Tools Do You Need For Web Scraping?
If you’re going to write a web scraper yourself — which requires coding knowledge — you’ll need the latest version of Java or Python. You’ll also need an automation tool like Maven and a class library you can use when building your scraper.
If you don’t want to go to all that effort, you can simply buy a web scraping bot that someone else has already written. Scraping Robot, for example, has several modules ready to go. Or you can get one custom-built.
Lastly, you’ll need proxies. Proxies mask your identity and provide an added layer of security online by sending a different internet protocol (IP) address to the server of the website you’re visiting. Blazing SEO’s data center proxies and rotating residential proxies are among the best, and they’re always ethically sourced.
While web scraping and web crawling are similar and often go hand-in-hand, they have different purposes. They also work via different processes.
Web crawling is immensely helpful for returning search data quickly. Web scraping, meanwhile, provides a wealth of data for businesses that can be targeted and used to provide valuable insights.
If you’re looking for more information on web scraping and proxies, check out the Blazing SEO blog. If you’re interested in using our proxy products, reach out for more information to find the one that’s best suited for your specific data-gathering needs.
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