What are the Differences between Web Crawling and Web Scraping?

Differences between web scraping and web crawling.

There are many ways to gather information from the internet, yet web crawling and web scraping are the two most common ones and while most people use these terms interchangeably in reality they are not the same thing.

What is web crawling?

Web crawling is the process of using tools to read, copy and store the content of the websites for archiving or indexing purposes. It is what the search engines like Google, Bing, and Yahoo do, they use crawling to look through the websites discover what content they include, and build entries for search engine index.

What is web scraping?

Web scraping is the process of extracting a large amount of specific data from online sources, the extracted data is often further interpreted and parsed by data analysts to make a more balanced to make more business decisions.

How web scraping and web crawling works

Web Crawling

Web crawling is performed by special bots or programs called web crawlers or web spiders. As a rule, web crawlers execute the following steps;

It visits the initial list of specific URLs also called seeds, during the visits the crawler locates the content on the web pages, conveys it to the database, and adds it to the search engine index after indexing it identifies other links found on the initial web pages and adds them to the frontier, then the crawler repeats the steps one through three with new links until frontier is empty.

Most sites use search engine optimization methods to make their content discoverable by web crawlers and thus rank higher in search engine results.

Web Scraping

Web scraping, this process is usually performed by special programs called web scrapers. Generally, data scraping consists of the following steps;

A web scraper takes the list of the URLs and loads all the HTML code for these websites, then it gathers all data or data of the predefined type, and finally, it downloads the data and saves it in SQL, XML, or excel format.

Tools used for data gathering methods

Web Crawlers

Among the most widely used are Apache Nutch, StormCrawler, Screaming Frog, Semrush, and Deep Crawl, all of them allow you to automate crawling activities and scan thousands of websites for the requested content.

Web Scrapers

Among the commonly used scarping tools are scraping bee, octoparse, Parse hub, and Finer, these apps can automate data extraction from multiple online sources as long as you know what type of content you are looking for.

Use Cases of Web Crawling and Web Scraping

Web Crawling

Used in generating search engine results.
Monitoring SEO analytics, to perform the most relevant keywords.
Perform website analysis to find common errors like pages that return 404 or 500 errors.

Web Scraping