Web Scraping Vs. Web Crawling: Key Difference and Concepts

Typically, companies require information and in substantial quantities. And frequently, when talking about how to acquire a large amount of data from the internet, we often use the terms “data extraction” and “data spying” interchangeably.

Perhaps, this is nobody’s fault and, at some level, correct. This is because before data extraction can even begin, some form of data spying (to find web pages with relevant data) has to occur. So technically speaking, data spying usually precedes data extraction.

However, both data spying and data extraction exist as separate concepts and have their differences. Today, we will see what these differences are and what is a data spy.

What is data extraction?

The process of data extraction can be defined as the retrieval of specific and valuable public data from multiple sources such as websites, marketplaces, social media platforms and so on.

Extracting the data involves using data extraction tools to interact with the target server, read its contents, retrieve the needful, return the data to the host computer, and then save it in some usable format.

The extracted data can then be analyzed further and deeper, interpreted and even used to make key business decisions that promote brand growth.

In today’s competitive market, it is believed that company successes are directly associated with how much of their decisions are data-driven. This makes data extraction a crucial part of any business adventure. 

What is data spying?

Data spying is also sometimes called “information gathering” and is defined as the process of using tools known as spies to read, copy, and store the public contents of websites. Data spying involves going on the internet searching for data requested by the internet user. Once found, spying even deeper using links and URLs included and then finally tying everything up by creating indices and collections. The process plays a vital role in data indexing and archiving, two essential aspects of Machine Learning.

The data spying technique is generally used by giant corporations and search engines such as Google and Bing to extract data, create copies, and index them to make data extraction easier for brands.

What is a data spy?

A data spy, also often called an “information agent”, is defined as a spy that can be used to scan the internet for important contents. The spy navigates the web and systematically goes through web pages using internal links and URLs,  exploring in details all that the website has to offer before correctly indexing all the information gathered.

Generally speaking, data spies are used by search engines to spy through a website, learning all about its contents. They go from page to page, collecting links and URLs as they do so. Then they spy the links afterward. You can get more info about data spies by visiting the Oxylabs website.

The above process could endlessly save for a set of policies that control how the data spy works. To make the process more coordinated and efficient, data spies are usually built to follow the following rules:

  • Spy on websites based on the relative importance and relevance of each web page instead of checking all publicly available data
  • Constantly revisit websites to ensure that recently updated contents are also indexed
  • Check the robots.txt.file before spying to ensure they follow specific rules.

Main difference between data extraction vs. data spying

Indeed, data spying is closely tied to data extraction. It is also true that data spying naturally leads to data extraction. Both processes are pretty similarly hence the reason many people use the terms interchangeably. Yet there is a world of difference between the two, and below are the main ones.

Data Extraction Data Spying
The primary purpose is for data retrieval from specific websites The primary purpose is for searching, collecting, and indexing web pages across the internet
Generally used by both small and large enterprises Employed mainly by large corporations only
It entails visiting only specific pages and downloading data without making copies of the pages It entails searching for content then finding other relevant contents and, in most cases, duplicating the contents
It is a dual process involving a data spy to find the content and a parser to return the data It is a single process needing only a data spy
Data extraction finds application in brand and price monitoring, brand protection, retail marketing etc. Data spying’s main application is to assist search engines to give more helpful search results to internet users
Data extraction does not need to follow the robots.txt rule Data spying always has to follow this rule.


Data spying and data extraction; two roads that lead to the same end. They even work similarly but knowing what data spies as well as how data extraction and data spying differ is important to help you understand which of the processes or tools your business needs is.

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  1. Guest

    The text provides a clear and concise explanation of the key differences between web scraping and web crawling. It effectively defines both concepts and highlights their distinct purposes and processes. The reader would find this information helpful in understanding the nuances between these two terms commonly used in the field of web data extraction.