Introduction

Before automating any web application, Selenium must first launch a web browser. Launching a browser is the first step in almost every Selenium automation script because all user interactions—such as opening websites, clicking buttons, entering text, and validating results—take place inside a browser.

Selenium WebDriver provides browser-specific classes such as Chrome(), Firefox(), Edge(), and Safari() to start different web browsers.

Starting with Selenium 4, browser driver management has become much simpler. Selenium Manager automatically downloads and configures the appropriate browser driver in most cases, eliminating the need to manually install drivers.

In this tutorial, you will learn how to launch a browser using Selenium WebDriver, understand the code, explore real-world applications, common mistakes, best practices, and frequently asked interview questions.

What is Browser Launching in Selenium?

Browser launching is the process of starting a browser session that Selenium WebDriver can control.

When a browser is launched:

A new browser window opens.
A WebDriver session is created.
Selenium establishes communication with the browser.
The browser becomes ready to execute automation commands.

Why Do We Launch a Browser?

Launching a browser allows Selenium to:

Open web applications.
Interact with web elements.
Execute automation scripts.
Validate application behavior.
Perform end-to-end testing.

Without launching a browser, Selenium cannot automate any web application.

Syntax

To launch Google Chrome:

driver = webdriver.Chrome()

Similarly, other browsers can be launched using:

driver = webdriver.Firefox()

driver = webdriver.Edge()

driver = webdriver.Safari()

Practical Example

The following example launches a new Chrome browser session and verifies that the browser has started successfully.

from selenium import webdriver


# Topic: 4. Your First Selenium Script - Launching a Browser
# Practice site: https://the-internet.herokuapp.com/
#
# webdriver.Chrome() starts a new Chrome browser session. Selenium 4 manages
# the driver automatically when Chrome is installed on the machine.


def test_launch_chrome_browser():
    driver = webdriver.Chrome()

    try:
        assert driver.session_id is not None
        assert driver.capabilities["browserName"] == "chrome"
    finally:
        driver.quit()

Output

Chrome browser launched successfully.

WebDriver session created.

Browser Name:
chrome

Assertions Passed.

Test Executed Successfully.

Understanding the Code

Import Selenium WebDriver

from selenium import webdriver

Imports the Selenium WebDriver module required for browser automation.

Launch Chrome Browser

driver = webdriver.Chrome()

Starts a new Google Chrome browser session.

If Chrome is installed correctly, Selenium creates a WebDriver session automatically.

Verify WebDriver Session

assert driver.session_id is not None

Checks whether Selenium successfully created a WebDriver session.

If the session ID exists, the browser has launched successfully.

Verify Browser Name

assert driver.capabilities["browserName"] == "chrome"

Verifies that Selenium launched the Chrome browser.

The capabilities dictionary contains information about the browser and WebDriver session.

Close the Browser

driver.quit()

Closes all browser windows and ends the WebDriver session.

Execution Flow

Import Selenium
        │
        ▼
Launch Chrome Browser
        │
        ▼
Create WebDriver Session
        │
        ▼
Verify Session ID
        │
        ▼
Verify Browser Name
        │
        ▼
Close Browser

Automation Testing Example

Suppose your company wants to automate login testing for a web application.

The first step is always launching the browser.

driver = webdriver.Chrome()

driver.get("https://company-app.com")

After the browser opens, Selenium can continue with login, form submission, and validation.

Real-World Example

Consider an online banking application.

Every automation test begins by launching the browser before navigating to the banking website.

driver = webdriver.Chrome()

driver.get("https://banking-app.com")

This prepares the browser for all subsequent automation steps.

Common Mistakes Beginners Make

Forgetting to Install the Browser

Selenium Manager requires the browser to be installed on the machine.

If Chrome is not installed:

driver = webdriver.Chrome()

may fail.

Always ensure the required browser is installed.

Forgetting to Close the Browser

Incorrect

driver = webdriver.Chrome()

The browser remains open after execution.

Correct

driver.quit()

Always close the browser after the test completes.

Using an Unsupported Browser Version

Older browser versions may not work correctly with the latest Selenium version.

Keep both Selenium and your browser updated.

Best Practices

Always use the latest version of Selenium.
Keep your browser updated.
Use Selenium Manager for automatic driver management.
Always close the browser using driver.quit().
Verify that the browser launches successfully before performing automation steps.

Conclusion

Launching a browser is the first and most fundamental step in Selenium automation. It creates a WebDriver session that allows Selenium to communicate with the browser and perform user actions.

With Selenium 4, launching browsers has become much easier thanks to Selenium Manager, which automatically manages browser drivers in most environments.

Understanding how browsers are launched is essential before learning website navigation, browser commands, locators, and web element interactions.

Frequently Asked Questions (FAQs)

What is browser launching in Selenium?