Howto use the Firefox browser in headless mode with Selenium

Question

How do I open a Firefox browser in headless mode using Selenium ?

Answer 1

This is built-in to Firefox and released on September 28, 2017 (FF56.0)

Headless Firefox works on Fx55+ on Linux, and 56+ on Windows/Mac.

The Firefox team has usage examples on their Headless documentation page.

Their NodeJS example:

var webdriver = require('selenium-webdriver'),
    By = webdriver.By,
    until = webdriver.until;

var firefox = require('selenium-webdriver/firefox');
var binary = new firefox.Binary(firefox.Channel.NIGHTLY);
binary.addArguments("-headless");

var driver = new webdriver.Builder()
    .forBrowser('firefox')
    .setFirefoxOptions(new firefox.Options().setBinary(binary))
    .build();

In summary it is taking a binary that supports headless and adding the -headless argument to the starting arguments.

For Java:

   firefoxBinary.addCommandLineOptions("--headless");

Answer 2

To enable headless Firefox using selenium-webdriver version 4.0.0-alpha.1 and node 8.x:

const { Builder } = require('selenium-webdriver');
const firefox = require('selenium-webdriver/firefox');
const options = new firefox.Options();
options.headless();
const driver = new Builder().forBrowser('firefox')
    .setFirefoxOptions(options).build();