What Is a Headless Browser and Its Applications? in 2024

Extracting dynamic content is more challenging than extracting data from static web pages. Elements in dynamic pages constantly change according to users’ data. Changes in a web page require reprogramming web scraping bots to match the new content display. 

Headless browsers are an efficient way to scrape dynamic website elements. In a headless mode, you don’t have to reprogram your web scraping bots or wait for graphic elements to load while scraping. 

The article provides an overview of headless browsers, explaining their function and usage, and also lists some of the most well-known headless browsers available.

The most popular headless browsers

What is a headless browser?

A headless browser is a regular web browser without a user interface. Icons, buttons, tabs, or drop-down menus which help users navigate a computer system don’t display on a computer screen. However, just like other browsers, you can:

• Navigate between pages,
• Click anything on the screen,
• Download any source,
• And upload data.

Why is a headless browser useful?

Headless browsers are particularly used for web testing and web scraping. In web testing, developers and test automation engineers use headless mode to run their tests. A headless browser helps organizations automatically extract data from websites in their data extraction/web scraping projects.  

Is a headless browser essential in web scraping?

If you aim to scrape dynamic content, webpage elements that constantly change based on user data and behavior, you will need a headless browser. Because most web crawlers are programmed to crawl static HTML web pages, you will need to render the entire page you want to crawl. Headless browsers extract data from web pages without rendering the entire page.

Headless browsers in practice: use cases, challenges & solutions

Data scraping

Headless browsers help users scrape websites based on HTML without rendering the entire page. You can use a headless browser to load the web page, render the HTML content and execute JavaScript. Some web scrapers come equipped with an integrated headless browser capability. This feature enables the extraction of data from complex websites that require actual user behavior. Such tools are particularly adept at navigating web pages that involve dynamic content or interactive elements.

Advantage:

You don’t have to wait for entire web pages to load, including images, videos, and other time-consuming visual elements, performing tasks more efficiently and faster.

Disadvantages:

• Dynamic web pages: The majority of web pages are HTML-based, and web structures are complicated. Web crawlers are designed to extract data from web pages based on their JavaScript and HTML elements.
• Slow load speed: When you crawl multiple web pages, your web crawler sends a request to the web server for each crawl. Most websites limit the number of requests/users allowed within a given time, called “crawl rate”,  to differentiate human user requests from automated ones. 

Recommendation:

Use proxies: You need to program your web crawler again after each change in web pages because the crawler will no longer be able to extract accurate data.

Dynamic proxies allow web crawling bots to overcome the crawl rate. You can integrate a dynamic proxy to your web scraper. Dynamic proxies change their IP address dynamically in each web scraping request and provide anonymity to web scraper bots.

Sponsored

Bright Data provides an all-in-one Scraping Browser API that comes equipped with integrated unblocking functionalities, including proxy rotation, CAPTCHA resolution, browser fingerprint management, and automated retry mechanisms. This API can be seamlessly incorporated into your existing web scraping setup, be it Puppeteer, Playwright, or Selenium.

Web testing

Headless browsers are commonly used for automation tests due to their efficiency and practicality. They offer the advantage of faster test runs, minimize the use of system resources, and are capable of operating in environments that lack a graphical user interface.

Developers and test automation engineers can run extensive automated web application testing using headless browsers, allowing to simulate user interactions such as form submission, navigating pages and clicking links. In headless mode, tests are run without Graphical User Interface (GUI), also known as “head”.  Headless browsers test all modern website structures such as HTML and CSS. 

Advantage:

Reduce the time of testing/run massive-scale web app tests: Browsers with GUI have to load images and icons. It takes time and increases the cost of testing for businesses. Since headless browsers do not load GUI, icons, tabs, bookmarks, etc., running tests on a server with no GUI is faster than running tests in other normal browsers. Moving your testing environment to a headless mode will reduce your testing costs.

Figure 2: The most time-consuming activities in a testing process

Disadvantage

Although headless browsers are very fast, and do not display graphical user interfaces, debugging issues may be difficult.

Recommendation

Do not use headless mode for an end to end testing (E2E testing). You need to test all functions and inputs from beginning to end to understand how the application or system performs clearly. Headless browsers have limited testing functions for testing real user scenarios.

What is headless browser testing?

The most common application of headless browsers is in testing web-based applications and websites. Headless testing refers to conducting browser tests without using the user interface (UI) or graphical user interface (GUI). In this approach, the testing process focuses on the functional components of a web application, while bypassing the graphical rendering of the UI elements. This means that the visual aspects of a webpage, like layout and design, are not rendered or visually checked during headless testing.

Regular UI-based browsers might be resource-intensive when executing parallel tests. The reduced resource usage of headless browsers makes them suitable for handling numerous tests running in parallel.

More on web scraping

• Using Proxies for Web Scraping: How-to, Types, Best Practices
• ETL Pipeline: What it is, Why it matters, Use Cases/Applications
• Email scraping: overview, use cases, challenges & best practices

If you want to learn more about headless browsers in web scraping you can reach us, and feel free to review our data-driven list of web scrapers: