How to make Firefox headless programmatically in Selenium with Python?

To invoke Firefox Browser headlessly, you can set the headless property through Options() class as follows:

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

options = Options()
options.headless = True
driver = webdriver.Firefox(options=options, executable_path=r'C:\Utility\BrowserDrivers\geckodriver.exe')
driver.get("http://google.com/")
print ("Headless Firefox Initialized")
driver.quit()

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There's another way to accomplish headless mode. If you need to disable or enable the headless mode in Firefox, without changing the code, you can set the environment variable MOZ_HEADLESS to whatever if you want Firefox to run headless, or don't set it at all.

This is very useful when you are using for example continuous integration and you want to run the functional tests in the server but still be able to run the tests in normal mode in your PC.

$ MOZ_HEADLESS=1 python manage.py test # testing example in Django with headless Firefox

or

$ export MOZ_HEADLESS=1   # this way you only have to set it once
$ python manage.py test functional/tests/directory
$ unset MOZ_HEADLESS      # if you want to disable headless mode

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Outro

How to configure ChromeDriver to initiate Chrome browser in Headless mode through Selenium?

The first answer does't work anymore.

This worked for me:

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

options = FirefoxOptions()
options.add_argument("--headless")
driver = webdriver.Firefox(options=options)
driver.get("http://google.com")

My answer:

set_headless(headless=True) is deprecated. 

https://seleniumhq.github.io/selenium/docs/api/py/webdriver_firefox/selenium.webdriver.firefox.options.html

options.headless = True

works for me