Reading and Writing Cookies in Selenium Python

When automating web applications using Selenium in Python, dealing with cookies is often essential. Cookies store session data, user preferences, authentication tokens, and other information that can help in navigating a site without repeating the same steps every time—like logging in. Understanding how to read and write cookies in Selenium gives you control over the browser session and enables smarter automation.

In this blog post, we’ll cover how to handle cookies in Selenium Python—reading, adding, saving, and loading cookies—with practical examples and tips.

What Are Cookies?

Cookies are small text files stored in the browser by websites. They typically hold data such as:

• Session IDs (for keeping users logged in)
• Preferences (e.g., language, theme)
• Tracking data (analytics or ad targeting)

In automation, cookies allow you to maintain session state or simulate specific scenarios without redoing every step.

Setting Up Selenium in Python

To get started, install Selenium (if not already installed):

bash

pip install selenium

You’ll also need a WebDriver. Here’s how to initialize one with Chrome:

python

from selenium import webdriver

driver = webdriver.Chrome()

driver.get("https://example.com")

Reading Cookies

Once you're on a page, reading cookies is simple:

python

# Get all cookies

cookies = driver.get_cookies()

for cookie in cookies:

    print(f"{cookie['name']} = {cookie['value']}")

# Get a specific cookie by name

session_cookie = driver.get_cookie("session_id")

print(session_cookie)

This is useful for checking whether authentication or preferences are set properly.

Writing (Adding) Cookies

You can add cookies manually to simulate a logged-in session or a specific user state.

python

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# Must navigate to domain before setting cookies

driver.get("https://example.com")

# Add a cookie

driver.add_cookie({

    "name": "session_id",

    "value": "123456abcdef"

})

After adding cookies, refresh the page to see them in action:

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driver.refresh()

Note: Cookies must match the domain currently open in the browser. You can't add cookies for a domain the driver hasn’t visited.

Saving and Loading Cookies (Persistent Sessions)

Save Cookies to File

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import json

cookies = driver.get_cookies()

with open("cookies.json", "w") as f:

    json.dump(cookies, f)

Load Cookies from File

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with open("cookies.json", "r") as f:

    saved_cookies = json.load(f)

driver.get("https://example.com")

for cookie in saved_cookies:

    driver.add_cookie(cookie)

driver.refresh()

This allows you to log in once manually, save the cookies, and reuse them for subsequent test runs—saving time and avoiding repetitive login automation.

Deleting Cookies

You can also delete cookies if needed:

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# Delete a specific cookie

driver.delete_cookie("session_id")

# Delete all cookies

driver.delete_all_cookies()

Useful for cleanup or testing how your app behaves without session data.

Best Practices

• Always navigate to the target domain before manipulating cookies.
• Use cookies to bypass logins only when secure and appropriate, especially in test environments.
• Clear cookies when tests are complete to avoid conflicts.
• Validate cookie properties such as expiry and path when debugging.

Conclusion

Reading and writing cookies in Selenium Python is a powerful technique that enhances your automation scripts by giving you direct control over browser session state. Whether you’re trying to bypass repetitive login flows, test personalized user experiences, or simulate session expiry, managing cookies can make your test suite faster, smarter, and more robust. Start small—read, add, and delete cookies—and build up to managing full session persistence for complex test scenarios.

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