Browser automation needs to mirror the real user experience. That means testing layouts, buttons, and navigation in the same screen conditions your users will see. One way to get closer to that reality is to maximize the window in Selenium before your test begins.
Without a maximized window, UI elements can shift, menus may collapse, or some parts of the page might remain hidden. That’s why window control in automation scripts is more than just a nice-to-have. It’s a baseline for reliable testing.
In this article, we’ll show you:
Let’s get started.
Automation works best when it reflects how users actually interact with your application. A real user opens a browser, adjusts the window, and navigates the full layout. To simulate this correctly, your tests need to manage the browser window with precision.
Many layout issues only appear under specific window sizes. Menus collapse, text wraps, and buttons shift. That’s why it's helpful to maximize the window in Selenium before your tests start. It gives your script a full view of the UI and helps surface visual issues early.
Selenium provides built-in commands for this. You can choose to maximize, minimize, resize to specific dimensions, or go fullscreen. These controls help you simulate different devices and test for consistent behavior across viewports.
When you manage the window size deliberately, you reduce test flakiness. Screenshots become easier to analyze. Your validations run against the actual layout, not a shrunken version. This is especially important for responsive design testing.
Use window control in Selenium to create stable tests that reflect real user behavior. It brings more confidence to every automated run.
Using the maximize window in Selenium method brings a series of advantages that help stabilize and improve your automation results. It sets a clean visual baseline for every test run.
For any test case that involves layout checks or dynamic content, maximizing the window gives you a better, more predictable result.
You can maximize the browser window in Selenium using a few simple commands. These steps help create a consistent viewport so your scripts behave the same way across machines.
Step 1: Import Selenium WebDriver in your Python script.
Step 2: Launch your preferred browser, such as Chrome or Firefox.
Step 3: Use the maximize_window() method to expand the window to its maximum size.
Step 4: Navigate to your target site. Then confirm the dimensions using get_window_size().
The code below shows a working example.
from selenium import webdriver
driver = webdriver.Chrome()
driver.maximize_window()
driver.get("https://katalon.com")
size = driver.get_window_size()
print("Window size:", size)
driver.quit()You can also try fullscreen_window() if your application needs complete screen coverage without browser chrome. This method gives you an immersive viewport for testing modal dialogs or video players.
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
# Configure ChromeOptions
chrome_options = Options()
chrome_options.add_argument("--disable-infobars")
chrome_options.add_argument("--start-maximized") # start in maximized mode
chrome_options.add_argument("--disable-extensions")
# chrome_options.add_argument("--headless") # uncomment to run headless
driver = webdriver.Chrome(options=chrome_options)
driver.get("https://katalon.com")
# Make browser go truly fullscreen (hides browser UI chrome)
driver.fullscreen_window()
size = driver.get_window_size()
print("Window size:", size)
driver.quit()fullscreen_window() expands the viewport beyond normal maximize (it removes toolbars and browser chrome) which is useful for modal dialogs or testing full-screen content.
ChromeOptions lets you pre-configure how Chrome launches — e.g. maximized, headless, or with/without extensions — before starting WebDriver.
Use maximize commands early in your script to standardize the environment. This is a great way to reduce layout surprises and improve test consistency.
Managing the browser window with intention improves the accuracy and reliability of your tests. It also helps you catch layout changes that only appear under specific screen conditions. Here are some best practices to get the most out of the maximize window in Selenium command and related methods.
By adding window management into your test flow, you help your automation behave more like a real user. It creates stronger coverage and gives your tests more visual confidence.
Katalon brings the full power of Selenium into a low-code platform that works for everyone. It simplifies test creation, enhances test stability, and helps teams scale automation with ease. While Selenium gives you raw browser control, Katalon wraps that power in a user-friendly interface built for speed and collaboration.
With Katalon, you can automate tests across browsers, devices, and environments—all without setting up infrastructure or writing complex scripts. It is designed for teams of all sizes and skill levels, from solo testers to enterprise QA teams.
Katalon extends the capabilities of Selenium with an enterprise-ready solution that is easier to adopt, faster to deploy, and built to scale. It is a modern testing platform designed to support the full automation lifecycle.
📝 For hands-on guidance, visit Katalon Docs. If you want to sharpen your skills, check out the structured lessons on Katalon Academy.