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Deep Dive into `headless=new` in Selenium


When it comes to automation testing, Selenium is a household name. With its extensive range of capabilities and flexibility, it has become an indispensable tool for quality assurance engineers. One of the most significant features of Selenium is its ability to run in headless mode, allowing testers to execute tests without the need for a visible browser instance. In this article, we'll delve into the world of headless mode, specifically exploring the `headless=new` parameter and its implications for Selenium testing.

What is Headless Mode?

Headless mode is a configuration option in Selenium that enables running browser instances without displaying a visible UI. This mode is particularly useful for automating tasks on cloud infrastructure, where a graphical interface is not available, or for running tests on a continuous integration/continuous deployment (CI/CD) pipeline. By default, when you use headless mode, Selenium will launch a browser instance in the background, allowing you to execute tests without visual rendering.

chrome headless=new
Chrome --headless old and new

Previously, headless mode was not just a mode but rather considered as another library. This meant that every feature had to be implemented separately for it, leading to a unique set of bugs not found in the Chrome library. Managing this not only demanded extensive effort from Chrome developers but also required users to handle a significant amount of customization for both headless and headed modes. As a result, the current setup illustrates that both headless and headfull modes utilize the same library, ensuring uniformity across functionalities. To delve deeper into the implementation details, you can refer to the blog post created by Chrome developers.

The `headless=new` Parameter

In recent Selenium versions, a new parameter called `headless=new` has been introduced. This parameter signals a significant shift in how headless mode operates. With `headless=new`, Selenium no longer treats headless mode as a separate entity from the standard, full-browser experience. Instead, it leverages the same codebase as the full-featured browser, ensuring that your tests are executed in a more authentic environment.

Why `headless=new` Matters

The introduction of `headless=new` addresses several limitations and drawbacks associated with traditional headless mode. I need to switch to the `--headless=new` because the old version is supporting the testing the Chrome extensions. I can create test cases and run it on headful mode but when I want to run it in headless mode in the CI, it starts failing. There many more benefits and some key benefits include:

  • Improved Compatibility: By sharing the same codebase as the full browser, `headless=new` ensures that your tests are executed in an environment that closely mirrors the real-world browsing experience.
  • Enhanced Stability: By leveraging the same rendering engine as the full browser, `headless=new` reduces the likelihood of issues and errors that were previously common in headless mode.
  • Simplified Maintenance: With `headless=new`, you can write tests that can be executed in both headless and full-browser modes, eliminating the need to maintain separate test suites.

Using headless=new in Selenium with Python

To take advantage of headless=new in Selenium with Python, follow these steps:

Install the required dependencies:

from selenium import webdriver
from import Options
from import Service
from import ChromeDriverManager

Import the necessary modules:

options = Options()

    Configure the Chrome options:pip install selenium 

    service = Service(ChromeDriverManager().install())
    driver = webdriver.Chrome(service=service, options=options)

    Create a new instance of the Chrome driver pip install webdriver-manager

    from selenium import webdriver
    from import Options
    from import Service
    from import ChromeDriverManager

    options = Options()

    service = Service(ChromeDriverManager().install())
    driver = webdriver.Chrome(service=service, options=options)


    Best Practices for headless=new

    When working with headless=new, keep the following best practices in mind:Use a recent version of Selenium: Ensure you're running the latest version of Selenium to take advantage of the headless=new features. Carefully consider your test environment: As headless=new uses the same codebase as the full Chrome browser, ensure your tests are designed to accommodate the increased resources required for headless mode. Monitor your system resources: Keep a close eye on system resources, such as memory and CPU usage, to avoid performance bottlenecks.


    In conclusion, headless=new marks a significant improvement in Selenium's headless mode capabilities. By leveraging the same codebase as the full Chrome browser, you can now execute tests in a more authentic environment, enjoying improved compatibility, stability, and maintenance. By following the best practices outlined in this article, you'll be well on your way to unlocking the full potential of headless mode in Selenium with Python.


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