Headless browsers 101: Data gathering made simple

Sharon Bennett 28 Apr 2023 7 min read

We mention headless browsers quite often when we talk about data gathering in our articles. This technology has gained a lot of popularity lately as a convenient option not just for web scraping but for testing, too.

So we thought: It will be great to dive deeper into headless browsers and provide you with a detailed overview of them. In this article, we’ll take a look at this tool, figure out how it works, what its use cases are, issues you might face, and the correct approach to such browsers.

What is a headless browser?

There is quite a lot of work behind a page that appears on the screen when we enter a certain website. A browser has to:

• Send a request to the destination server,
• Process the answer, and
• Display it on our device in a way we’ll be able to understand.

For us, it takes a couple of seconds and clicks. Under the hood, however, the browser performs a lot of processes, especially when it comes to displaying the content for us. Here's a crucial difference:

A headless browser does all the work needed to take you to a requested page but without displaying its content. In other words, headless browsers don’t have a graphical user interface — a "head".

When it comes to everything else, it’s just like any other browser you know: It can click buttons, navigate through websites, download and upload content, and so on. You just won’t see a pretty picture of all this activity.

The advantage of headless browsers is that they are more lightweight and way quicker than the usual ones because they lack the user interface. That’s why they’re used for data gathering and testing — to speed up the process without overloading the computer.

Use cases for headless browsers

This tool is quite versatile, and both web developers and data scientists utilize it a lot. Here are some of the situations where a headless browser is an essential tool.

Data gathering

As you already know, headless browsers are widely used for scraping. Running this process through a normal browser would be complete overkill for a computer. Moreover, it’s way faster to go to a web page using a headless browser, gather all the data without the user interface, and go to the next page. Additionally, this tool allows for automating this process — more on that below.

❔ Further reading: How to Protect Your Brand with Web Scraping and Proxies

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Automation of processes

A headless browser can automate not only web scraping but other processes too. For example, developers use this instrument to automate scripts, website interactions, and user interface tests. Thus, they can run these processes faster in a browser environment. To ensure the bot's safety (i.e. to avoid getting blocked by the anti-bot systems), they may add a library of headers and fingerprints to their scraper.

Improving performance

To track system uptime and performance, developers need to run small quick tests to check if the given system component is working correctly. The user interface is not necessary for such tasks, meaning that a headless browser would allow performing these actions quicker as the interface won’t have to load.

Style elements testing

While a website layout is a user interface itself, you don’t need a GUI to test style elements such as font type and color, page width, and so on. A headless browser that "understands" HTML and CSS is a great tool for quick layout testing. Also, it allows headless testing for JavaScript and AJAX execution, and capturing screenshots of these check-ups.

Other use cases

There are other miscellaneous processes that can benefit from headless browsers. Using them you can:

• Generate screenshots and PDFs of web pages,
• Monitor the performance of online apps,
• Diagnose website performance using a timeline trace,
• Simulate browsers,
• Run various tests, and more.

Potential issues with headless browsers

Since this tool allows to automate processes and improve them with the use of different libraries, malefactors use it for fraud. Using headless browsers along with bots they can:

• Generate fake leads, thus taking down advertisement campaigns and flushing ad budgets of businesses (i.e. ad fraud.)
• Create fake accounts for various needs — from black hat marketing to phishing.
• Perform DDoS attacks since headless browsers allow to automate and speed up requests to the destination server.
• Generate fake web traffic.

We’re sure there are more malicious ways to use this tool. Yet, we’ve mentioned the most widely-spread ones to give you an idea of how malefactors can benefit from headless browser. You need to know this detail if you’re going to gather data using such an instrument. There already are sophisticated tools that help website owners detect and stop headless browsers. Therefore, you might experience difficulties during web scraping.

To avoid issues, use residential proxies that will let your scraper appear as a real user to a destination server. Infatica offers different plans that can satisfy various data gathering needs. Also, we can create a custom plan tailored for your needs. We constantly add new proxies to our pool to provide you with clean and ready-to-use IP addresses — that’s why you can enjoy smooth and fast web scraping with Infatica.

Additionally, you should use libraries of headers that will make the requests a scraper sends appear as those real users would send.

How to choose a headless browser?

Different headless browsers are more suited for different needs. We will list the most popular tools and describe them briefly to let you understand which one to choose considering the type of activity you’re going to perform.

Headless Chromium

Google provides headless mode for Chrome, turning it into a lightweight and fast headless browser. A headless Chrome browser will be perfect for:

• Data gathering,
• PDF file creation,
• Screenshot creation, and
• Multi-level navigation testing.

Mozilla Firefox

Firefox supports headless mode as well. Although you’ll need Selenium, Slimmer JS, or W3C WebDriver to run it in this mode. Headless Firefox can be used for:

• Testing,
• Headless automation,
• Scripting, and
• Basic unit tests.

Speaking of Selenium, we also have a comprehensive overview of Python web crawlers.

PhantomJS

PhantomJS headless WebKit is created to work with the complexities of the internet landscape with the use of command-line testing. This tool is open source and used to be constantly improved by developers, who used it for:

• Navigation testing,
• Screenshot creation,
• User behavior simulation, and
• Working with different assertions.

Please note that PhantomJS development was suspended in 2018 — although the software itself is still functional, its lack of updates may render it obsolete in the near future.

HtmlUnit

This is a Java-based headless browser that’s suited for Java code. HtmlUnit can simulate different browsers to provide developers with the necessary environments. It’s good for testing lots of things such as:

• Forms,
• Links,
• Redirects,
• Performance of HTTPS pages and HTTP headers, and
• HTTP authentication.

The bottom line

Headless browsers are versatile and great for data gathering as well as other things. Just don’t forget to add Infatica proxies to the list of your web scraping tools for a smoother and faster process. If you have more questions left about the use of proxies for data gathering, just contact us. We’ll do our best to make things clear for you.

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