How to Run Headless Firefox with Python Selenium

Headless Firefox is a way to run an automated version of the browser that has no graphical user interface (GUI). Running any app without its graphical user interface significantly reduces the computational load, allowing you to perform tasks more quickly and efficiently or run more instances of the browser at once.

Both cases are highly useful in browser automation and web scraping applications. The former lets you run more tests without overloading your device, while headless mode with the latter lets you extract data at a greater scale.

What Is Headless Firefox?

Headless Firefox is the same browser as Mozilla Firefox, except it runs without the graphical user interface, meaning that it’ll be performing actions completely in the background. Nothing is visible directly to the user.

Since there’s no direct user interaction through the GUI, headless Firefox can only be run through browser automation. You need to program in the commands and actions for headless Firefox ahead of time.

A popular option for headless browsers is Selenium. It’s a Python library that provides access to automated browsers such as headless Firefox or Chrome. All you need to do is use the library to program in specific actions for the browser and run the application.

As you need to program in the actions through Python, headless Firefox isn’t all that useful for daily activities. Automated testing and web scraping are two areas where it excels, however, since headless Firefox consumes significantly less computing power and performs actions much quicker than regular Firefox.

Advantages of Headless Firefox

There are many advantages to running headless Firefox when compared to the regular headful mode. Most of the benefits come from the fact that headless mode requires less resources and is far more efficient than headful mode.

Speed, Performance, and Efficiency

Headless mode foregoes the GUI, which greatly reduces the time it takes to load the Firefox browser. As such, most headless browsers start, act, and run much faster than a headful one. Additionally, since it takes up less resources, you can run many more instances at once.

Finally, scripts and any programmed commands also run much faster in headless mode. So, there are many benefits in terms of performance when running headless mode.

Ideal Scenarios for Usage

As mentioned previously, not all use cases will be able to take advantage of all of the performance benefits. For regular internet surfing, the headful Firefox browser will be much more useful. Headless mode is much better for:

• Automated testing

Headless mode works faster and lets you run more instances, which means more tests in a shorter period of time.

• Data extraction

Web scraping thrives on headless mode as you need to run through a lot of pages in quick succession, which is exactly what a headless Firefox browser does.

• Server-side automation

As long as server-side rendering is not required, you can run a lot of tests on servers through headless mode.

All of the above tasks (and any other tasks that do not require visual input) work great with headless mode due to increased efficiency. There’s plenty of limitations to headless mode, however.

Limitations of Headless Firefox

Many of the drawbacks of headless mode come from the fact, again, that there’s no GUI. Any visual feedback is automatically lost, making it impossible to perform visual tasks. Additionally, some parts of debugging may be difficult due to no visual feedback.

JavaScript features could be an issue as well. Headless mode may be unable to execute some functions fully, making scraping and debugging harder. Finally, a headless browser may not have all of the functionality and features a headful one has.

Running Headless Firefox With Python and Selenium

To execute a headless Firefox webdriver instance, you’ll need an IDE (such as Pycharm), Python, and the Selenium library. Assuming you have two of the former, open the Terminal in your IDE and run:

pip install selenium

Previous Selenium versions required you to download headless versions of browsers manually before you could initiate a webdriver instance. Current Selenium versions come with most headless versions pre-installed, so you can jump into running a webdriver instance right off the bat.

from selenium import webdriver
from selenium.webdriver.firefox.options import Options

options = Options()
options.add_argument("--headless")
driver = webdriver.Firefox(options=options)

driver.get('http://iproyal.com')
print(driver.title)
driver.quit()

There are two key aspects in our script. First, we import the Selenium webdriver function. It’ll be used to create a headless instance of any browser. Additionally, we import the options function for Firefox’s selenium webdriver, so we can add headless mode as browsers run in headful by default.

Firefox vs. Headless Chrome: A Comparison

Chrome is another popular option for headless Selenium webdriver instances. In fact, it’s likely the more popular option, however, it’s not always strictly better than Firefox:

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