How Does Web Scraping Work?

Aftab Vasiwala
Read Time: 7 Minutes
How Does Web Scraping Work?

Web scraping. You may have heard the term, but (like most people) have no idea what it means. Of course, this is all well and good if you’re entirely uninterested in internet technologies, but if you’re running an online business (or, indeed, any business with a web presence), it’s worthwhile understanding what this term means. 

Why? Put simply, web scraping can be used to help your business in a number of ways — from understanding your customer’s needs to sussing out your competition. Intrigued? If so, read on, as we provide a comprehensive guide to web scraping and how it works. Also, we recommend checking a web scraping API like ZenRows.

What is web scraping?

In 1993, the first web robot, the World Wide Web Wanderer, was created by Matthew Gray at the Massachusetts Institute of Technology. This web crawler was used to measure the size of the internet, and it was later instrumental in the creation of an index called the Wandex. The Wanderer marked an important milestone in the development of web scraping and the modern internet. This pioneering crawler was the first of its kind, and it laid the groundwork for many of the technologies and practices that we now take for granted.

Mere months later, the first crawler-based web search engine, JumpStation, was created. This bot indexed millions of web pages, making it possible to search the internet in a way that had never been possible before. It’s almost laughable to imagine now, but before the invention of JumpStation, websites relied on human administrators to collect and organize links — what a job to be tasked with! JumpStation's use of a crawler revolutionized the way we access and search the web, paving the way for modern search engines like Google.

Web scraping has become far more advanced since its invention in the 1990s, but the underlying premise remains the same — it’s simply a technique used to extract data from websites. It typically involves the use of two components: a crawler and a scraper. The crawler is an AI algorithm that navigates (or crawls) the web, following links to find data specified by the user. On the other hand, a scraper is a tool used to extract this data from the website, often using specialized techniques to gather information quickly and accurately. 

While it is possible to manually collect this data, using specialized tools is often more efficient and accurate. Many pre-built scrapers also come loaded with additional features: for example, the ScrapingBee API is capable of bypassing rate limiting, lowering the chance of your bots getting blocked while scraping the web for valuable data — which is handy!

Overview of the web scraping process

Typically, a web scraper is given one or more URLs to scrape, and it then loads the HTML code for the page(s). More advanced scrapers will also render CSS and JavaScript elements to fully capture the website's content. Think of HTML as the scaffolding of the website, with CSS and Javascript providing visual aesthetics and interactivity, respectively. 

Once the scraper has loaded the webpage, it can then either extract all the data it rendered or sift through and pick out specific data points determined by the user. Once that’s taken care of, the data can then be saved in a variety of formats — such as Excel or CSV — for further analysis. Some web scrapers can even convert the data into a JSON file for use as an API. 

What can web scraping be used for?

Now we’re clear on the origins of web scraping and how it works, let’s examine some of the ways businesses can use web scraping tools to their advantage.

  • Market research — the data gathered through scraping can be used to gain insights that can inform important business decisions, such as market trend analysis, pricing strategies, and research and development efforts. By using a scraper to collect data from relevant websites, businesses can gain a competitive edge and make more informed decisions. 

  • Lead generation — manually copying and pasting contact information from websites can be time-consuming and extremely laborious work, but web crawlers can automate this process and display it in an easily-digestible format. 

  • Price and product intelligence — another common use for web scraping is to collect information about competitors' prices and products. This type of data can be valuable for businesses looking to automate their pricing strategies and improve their market positioning.

  • Brand monitoring — in the past, determining how people felt about your brand meant manually searching the internet for reviews and social media interactions. However, with the use of web scraping API, businesses can quickly and easily collect this data. By using a web scraping API, marketing and PR teams can track customer opinions and sentiments, which can help them make more informed decisions.

  • Investing — web scraping for finance can be used to garner insights from SEC filings, estimate the fundamentals of companies, and monitor news and public sentiment, which can then be used to make informed investment decisions. 

    Web scraping for finance has emerged as a powerful tool for investors seeking to gain valuable insights into companies and markets. By leveraging this technology, investors can extract data from various sources such as SEC filings, news articles, and social media platforms to inform their investment decisions.

    One key application of web scraping in finance is the analysis of SEC filings. Companies are required to file various documents with the Securities and Exchange Commission (SEC), including quarterly and annual reports, which contain crucial information about their financial performance, operations, and future outlook. By systematically scraping and analyzing these filings, investors can estimate the fundamentals of companies, such as revenue, earnings, and cash flow, and assess their overall health and prospects.

Types of web scraping

There are many different types of web scrapers, and each one has its own set of unique characteristics. Let’s go over some of the main differences between each type.

Self-built vs. pre-built

While it is possible for anyone to build their own web scraper, doing so requires quite an advanced level of programming knowledge (though beginner’s guides do exist).

Of course, this means that the complexity of the scraper will depend entirely on the technical know-how of the developer creating it. A much more convenient alternative is to opt for a pre-built web scraper, of which there are many available for download on the web. These scrapers may include advanced features such as scheduling, exports to JSON and Google Sheets, and more.

Overall, the choice between building a custom scraper and using a pre-built one will depend on the specific needs and goals of the user (along with their proficiency in software engineering!).

Cloud vs. local

Local scrapers run on the user's own computer, using its resources and internet connection. This means that the scraper can potentially slow down the computer and impact the user's data usage.

Cloud-based scrapers, on the other hand, run on off-site servers provided by the scraper's developer. This frees up the user's computer, allowing them to continue working while the scraper runs. Cloud-based scrapers may also offer advanced features such as IP rotation, which can help prevent websites from blocking the scraper due to its scraping activity. 

User interface

The user interface of a web scraper can vary greatly, depending on the specific tool and its intended use. Some scrapers have a minimal interface, with only a command line for input and output. This type of interface can be difficult for non-technical users to understand and use. Other scrapers have a more user-friendly interface, with a fully-fledged UI that renders the website and allows the user to easily select the data they want to scrape.

Stand-alone programs vs. browser extensions

Browser extensions are app-like programs that can be added to your web browser. Truthfully, they’re a bit of a double-edged sword, because while this makes them exceptionally easy to use, they’re also often limited in terms of their capabilities.

In contrast, stand-alone web scraping programs may not be as convenient as a browser extension, but they’re typically more powerful and can handle more advanced tasks.

Benefits and drawbacks of web scraping

So, you know what web scraping is, and you’re aware of some of the main types of web scrapers available — what now? Let’s weigh up the pros and cons of web scraping.

Advantages of web scraping

  • Web scraping allows you to collect large amounts of data quickly and efficiently.

  • It can be used to automate tedious and time-consuming tasks, such as collecting data from multiple websites.

  • Web scraping can help you save time and resources by allowing you to extract only the data that you need, rather than downloading entire websites or large volumes of data.

  • It can also be used to monitor prices and other information on websites, which can be useful for businesses and consumers.

  • Web scraping can help you uncover hidden data and insights, which can be valuable for research and analysis.

  • It can also help you keep track of competitors and stay up-to-date with industry trends.

Limitations and challenges of web scraping

  • Web scraping can be complex and require some technical knowledge to set up and use effectively.

  • Some websites may not allow web scraping, and you may need to obtain permission before collecting data from them.

  • Web scraping can put a strain on a website's server, which can slow down or crash the site.

  • The data that you collect through web scraping may not be accurate or up-to-date, and you may need to clean and verify it before using it.

  • There may be legal limitations on the use of web scraping, depending on the country and the type of data you’re collecting.

  • Web scraping can be unethical if it involves collecting sensitive or personal information without the consent of the individuals concerned.

The bottom line

Web scraping can be a valuable tool for collecting the data you need, but the process can feel overwhelming if you're not familiar with it. Hopefully, our guide has cleared up any confusion you may’ve been feeling about the topic! For more information on boosting your business endeavors, check out our guides on optimizing your site for local SEO or improving your eCommerce UX.

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