Selenium
The original browser automation tool — drives a real browser through the WebDriver protocol.
What it is
Selenium is a powerful Python library for automating web browsers. It allows you to programmatically interact with web pages, simulate user actions, and perform browser testing across multiple browsers.
Selenium allows you to control browsers using WebDriver. You can navigate pages, click buttons, fill forms, extract text, take screenshots, handle alerts, and perform automated testing. It supports Chrome, Firefox, Edge, Safari, and other major browsers.
- Watch for
- Explicit waits are essential — implicit waits are the main source of flaky Selenium tests
- Licence
- Apache 2.0
When to use it
The question documentation cannot answer for you — because it cannot recommend something else.
Reach for it when
- Testing against browsers and versions Playwright does not cover
- An existing test suite already built on it
- Legacy enterprise environments where WebDriver is the sanctioned standard
Look elsewhere when
- Starting fresh — Playwright is faster, less flaky and has better waiting semantics
Installation
pip install seleniumGetting started
The smallest useful thing you can do with it, and what each part means.
from selenium import webdriver
driver = webdriver.Chrome()
driver.get('https://example.com')
print(driver.title)
driver.quit()from selenium import webdriver
from selenium.webdriver.common.by import By
driver = webdriver.Chrome()
driver.get('https://example.com')
element = driver.find_element(By.ID, 'username')
element.send_keys('myuser')
driver.quit()Advanced usage
Where the library earns its place over a simpler alternative.
from selenium.webdriver.common.by import By
button = driver.find_element(By.XPATH, '//button[text()="Submit"]')
button.click()from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
wait = WebDriverWait(driver, 10)
element = wait.until(EC.presence_of_element_located((By.ID, 'result')))alert = driver.switch_to.alert
alert.accept()driver.save_screenshot('screenshot.png')from selenium.webdriver.chrome.options import Options
options = Options()
options.headless = True
driver = webdriver.Chrome(options=options)Errors and fixes
The failures you are most likely to hit, and what actually resolves them.
- NoSuchElementException
- Verify the selector used to locate the element and ensure it exists on the page.
- WebDriverException: Message: 'chromedriver' executable needs to be in PATH
- Download the correct WebDriver for your browser and ensure it is in your system PATH.
- TimeoutException
- Increase the wait time or check that the expected condition is correct.
Best practices
- Use explicit waits (`WebDriverWait`) instead of arbitrary sleep times for stability.
- Close or quit browser instances to free resources.
- Use headless mode for automation scripts that don't require UI interaction.
- Leverage browser-specific options and capabilities for optimized performance.
- Keep WebDriver versions compatible with the browser version installed.
Alternatives
Comparable options, and the reason you would pick one over the other.
Background
Why it exists, and what it was reacting to.
Selenium was originally developed in 2004 by Jason Huggins at ThoughtWorks as an internal tool for automated testing of web applications. Over time, it evolved into a widely-used framework for browser automation, supporting multiple programming languages and browser drivers. Selenium WebDriver became the standard API for reliable cross-browser automation.