Introduction

With the release of Selenium 4, Selenium Grid was completely redesigned to make distributed test execution simpler, faster, and easier to manage. Unlike Selenium Grid 3, which required separate Hub and Node configurations, Selenium Grid 4 introduces a modern architecture that supports standalone mode, distributed mode, Docker integration, improved scalability, and a built-in web interface for monitoring Grid sessions.

Selenium Grid 4 enables testers to execute Selenium tests across multiple browsers, browser versions, operating systems, and machines simultaneously using a simplified setup. It also provides better session management, improved stability, and enhanced compatibility with modern cloud platforms and CI/CD pipelines.

Today, Selenium Grid 4 is the recommended version for new Selenium automation frameworks and enterprise-level test execution.

In this tutorial, you’ll learn what Selenium Grid 4 is, its new features, how it differs from Selenium Grid 3, and how to execute Selenium tests using Selenium Grid 4.

What is Selenium Grid 4?

Selenium Grid 4 is the latest version of Selenium Grid that allows Selenium tests to run on multiple browsers, operating systems, and machines simultaneously using an improved and simplified architecture.

Compared to Selenium Grid 3, it offers:

Simplified setup.
Better performance.
Improved scalability.
Built-in Grid UI.
Better Docker support.
Enhanced session management.
Modern distributed architecture.

It is the recommended version for all new Selenium automation projects.

Why Use Selenium Grid 4?

Selenium Grid 4 provides several advantages:

Faster test execution.
Parallel execution.
Cross-browser testing.
Cross-platform testing.
Simplified configuration.
Built-in monitoring dashboard.
Better scalability.
Improved CI/CD integration.

New Features in Selenium Grid 4

Some of the major improvements introduced in Selenium Grid 4 include:

Standalone Mode

A single command starts both the Grid server and node on the same machine.

Ideal for learning and small automation projects.

Distributed Mode

Grid components such as Router, Distributor, Session Queue, Session Map, Event Bus, and Nodes can run separately.

Suitable for enterprise-scale automation.

Built-in Grid UI

Selenium Grid 4 includes a web-based dashboard that allows you to:

View connected nodes.
Monitor active sessions.
Check browser availability.
Observe test execution.

Better Docker Support

Grid 4 works seamlessly with Docker containers, making it easier to create scalable browser environments.

Improved Session Management

Sessions are managed more efficiently, resulting in better stability and reduced execution failures.

W3C WebDriver Standard

Selenium Grid 4 fully supports the W3C WebDriver protocol, improving browser compatibility and standardization.

Selenium Grid 3 vs Selenium Grid 4

Feature	Selenium Grid 3	Selenium Grid 4
Architecture	Hub and Nodes	Modern distributed architecture
Setup	More configuration	Simpler configuration
Built-in UI	No	Yes
Docker Support	Limited	Excellent
Session Management	Basic	Improved
W3C WebDriver	Partial	Full support
Scalability	Good	Better
Performance	Good	Improved

Example

from selenium import webdriver

from selenium.webdriver.chrome.options import Options


def test_selenium_grid4():

    options = Options()

    driver = webdriver.Remote(

        command_executor="http://localhost:4444",

        options=options
    )

    try:

        driver.get(
            "https://www.testmuai.com/selenium-playground/"
        )

        assert "selenium-playground" in driver.current_url

    finally:

        driver.quit()

Understanding the Code

Import Required Modules

from selenium import webdriver

from selenium.webdriver.chrome.options import Options

The required Selenium modules are imported.

webdriver is used to create a remote browser session.
Options stores Chrome browser configuration.

Create Chrome Options

options = Options()

A Chrome Options object is created.

Browser-specific settings can be added to this object before connecting to the Grid.

Connect to Selenium Grid 4

driver = webdriver.Remote(

    command_executor="http://localhost:4444",

    options=options
)

The Remote() method connects the Selenium test to a Selenium Grid 4 server running at:

http://localhost:4444

Instead of launching Chrome locally, the Grid selects an available node and starts the browser remotely.

Open the Application

driver.get(
    "https://www.testmuai.com/selenium-playground/"
)

The remote browser opens the Selenium Playground application.

The test interacts with the remote browser exactly as it would with a local browser.

Verify the Current URL

assert "selenium-playground" in driver.current_url

The assertion verifies that the application has opened successfully.

Close the Browser

finally:

    driver.quit()

The browser session is closed after the test execution.

Selenium Grid 4 Modes

Selenium Grid 4 supports multiple deployment modes.

Standalone Mode

Runs the Grid and Node together on a single machine.

Best for:

Learning Selenium Grid
Local execution
Small automation projects

Hub and Node Mode

Runs the Grid server separately from browser nodes.

Suitable for medium-sized automation frameworks.

Distributed Mode

Separates Grid components into independent services.

Best for:

Enterprise automation
Large-scale testing
Cloud infrastructure

Docker Mode

Runs Selenium Grid using Docker containers.

Widely used in modern CI/CD pipelines.

Practical Example

Suppose an online shopping website needs to be tested on Chrome, Firefox, and Edge running on Windows and Linux.

Using Selenium Grid 4, the automation framework distributes the test suite across multiple browser nodes. The tests execute simultaneously, significantly reducing the overall execution time.

Automation Testing Example

Consider an online banking application.

The regression suite contains thousands of Selenium test cases. Selenium Grid 4 distributes these tests across multiple remote browser nodes. Jenkins triggers the tests after every deployment, and the Grid executes them in parallel on Chrome, Firefox, and Edge, providing faster feedback to the QA team.

Real-World Example

Selenium Grid 4 is widely used in:

Selenium Automation Frameworks
Jenkins Pipelines
GitHub Actions
Azure DevOps
Docker-based Test Environments
Banking Applications
Healthcare Systems
E-commerce Platforms
Enterprise Automation Projects

It enables efficient parallel execution and large-scale cross-browser testing.

Advantages of Selenium Grid 4

Simplified setup.
Faster execution.
Parallel testing support.
Cross-browser compatibility.
Cross-platform testing.
Built-in monitoring dashboard.
Better Docker integration.
Improved scalability.
Full W3C WebDriver compliance.

Common Mistakes Beginners Make

Using Selenium Grid 3 Commands

Selenium Grid 4 introduces new startup commands and architecture. Always use the commands recommended for Grid 4.

Forgetting to Start the Grid

The Selenium Grid server must be running before Selenium tests can connect.

Assuming All Browsers Are Available

Only browsers installed on connected nodes can execute tests.

Ignoring the Grid Dashboard

Use the built-in Grid UI to monitor active sessions, nodes, and browser availability.

Best Practices

Use Selenium Grid 4 for all new automation projects.
Execute regression suites in parallel.
Use Docker for scalable Grid deployment.
Monitor Grid health using the built-in dashboard.
Keep browser versions updated.
Integrate Selenium Grid 4 with CI/CD pipelines.
Use Remote WebDriver for distributed execution.

Conclusion

Selenium Grid 4 is the modern and recommended version of Selenium Grid, offering simplified configuration, improved scalability, better performance, and built-in monitoring capabilities. It enables efficient parallel execution across multiple browsers and operating systems while integrating seamlessly with Docker and CI/CD pipelines. These enhancements make Selenium Grid 4 an essential tool for professional Selenium automation frameworks.

Frequently Asked Questions (FAQs)

What is Selenium Grid 4?

Selenium Grid 4 is the latest version of Selenium Grid that enables parallel execution of Selenium tests across multiple browsers, operating systems, and machines using an improved architecture.

What are the major improvements in Selenium Grid 4?

Key improvements include:

Built-in Grid UI
Standalone mode
Better Docker support
Improved session management
Distributed architecture
Full W3C WebDriver support

Does Selenium Grid 4 replace Selenium Grid 3?

Yes.

Selenium Grid 4 is the recommended version for new automation frameworks because it offers better performance, easier configuration, and more features.

Can Selenium Grid 4 be used with Docker?

Yes.

Selenium Grid 4 provides excellent Docker support, making it easy to create scalable and containerized test environments.

Is Selenium Grid 4 used in professional automation frameworks?

Yes.

Most modern Selenium automation frameworks use Selenium Grid 4 for parallel execution, cross-browser testing, Docker-based deployments, and CI/CD integration.

Key Takeaways

Selenium Grid 4 is the latest and recommended version of Selenium Grid.
It provides simplified setup, improved scalability, and better performance.
It supports Standalone, Hub and Node, Distributed, and Docker deployment modes.
The built-in Grid UI helps monitor nodes and test sessions.
Selenium Grid 4 is widely used in enterprise automation frameworks and modern CI/CD pipelines.