Using Selenium Grid for Distributed Test Execution and Faster Feedback

Selenium Grid is a very important part of the Selenium suite of tools that facilitate software testing. It is a tool that comes with many handy features that allow the user to perform a testing process for cross-browser testing in a very simple and seamless manner. In today’s world, the software company brings new updates to its software to stand in this competitive market. Selenium Grid helps to execute this testing process in a distributed manner.

Distributed testing is the process of optimizing the testing resources in parts and sharing the testing components with them to increase testing efficiency and save money and time. In this article, we will discuss what Selenium Grid is, distributed test execution, the importance of Selenium Grid in distributed test execution for cross-browser compatibility, etc.

What is a Selenium Grid?

Selenium Grid is an open-source tool that is used to perform automated testing for websites and web applications. Using Selenium Grid, you can perform cross-browser testing across many systems and browsers parallelly. It works as a central hub from which you can control the distribution of all your test cases for multiple machines. That is why

Selenium Grid provides scalability and efficiency to your testing process. As the Selenium Grid allows you to run your test cases in a distributed system to the nides, it reduces the testing time to a very large extent. Also, you get very fast feedback for their current testing process using Selenium Grid; it helps to make the changes in your existing project and run the test cases easily.

The quality and dependability of web applications are ensured by their distributed design, which enables organizations to obtain thorough test coverage across a variety of configurations and situations. Teams are given better testing tools, more productivity, and the capacity to produce high-quality software thanks to Selenium Grid. Now let us have a brief look over the architecture of Selenium Grid for cross-browser testing.

The Architecture of Selenium Grid

The Selenium Grid follows a distributed architecture. There are two components in this architecture. The first component is Hub, and the second component is the Nodes. There is one hub in a Selenium Grid and multiple nodes.

  • Hub: The hub acts as the central command for the entire Selenium Grid. It is responsible for receiving the test requests, and then it distributes them to the various nodes according to the requirement and type of requests. It receives, sends, and distributes the requests and also collects the results from all the nodes. In a Selenium Grid, there is only one hub.
  • Nodes: Nodes are the individual machine or systems in the Selenium Grid. It is responsible for receiving test requests from the hub and then processing them accordingly. Each of the nodes may host one browser for cross-browser testing. And after processing all the tests, it sends the results to the hub to process further.

Why Selenium Grid for Distributed Test Execution?

There are many other testing tools available for cross-browser testing. But why is Selenium Grid the most preferred tool among the testers? there are two reasons for that which are described below:

  • Platform compatibility: Selenium Grid provides you the option to execute your testing process across different types of platforms. Suppose you perform the testing process. And you have Internet Explorer 9 in the hub. And there are many nodes for that. So, there may be IE 8 for one node, IE 10 for another node, and things like that. In this case, the Selenium Grid becomes platform-independent. It makes this tool popular among the cross-browser testing community.
  • Parallel Test Execution: Using Selenium Grid to perform the testing process parallelly reduces test execution time. Executing parallel testing is what makes software testing productive and effective, though, along with those other factors. For instance, if you were to run a test case that takes 10 minutes to complete in parallel, it would only take 10 minutes to complete the task of testing a combination of 10 distinct browsers and devices. So, using the concept of parallel testing by using the selenium grid helps to test the browser on a large number of web browsers.

To leverage the distributed test execution, the use of a AI-powered test orchestration and test execution platform like LambdaTest, which is also a digital experience testing platform, can be used. It’s an online Selenium Grid that allows Selenium automation testing across a large farm of 3000+ browsers, OS, and devices. Using LambdaTest, you can have better test coverage and ensure the working of the website and web application seamlessly across all different platforms. You can scale your test infrastructure effortlessly based on your testing requirements, ensuring quick and reliable test execution, even with large test suites.

Advantages and Disadvantages of Selenium Grid

As we know, Selenium Grid is very popular and useful in distributed testing. But everything has its advantages and disadvantages. Let us see them briefly in the given section:


  • It saves time to execute the distributed testing technique. The saved time can be used for other purposes of the organization.
  • Selenium Grid provided an option to choose the Runtime Environment. You can customize the parameters of the runtime environment. If any test fails due to any reason, Selenium Grid allows us to diagnose the failures. You can detect and rectify the issue in the next iteration of the testing process.
  • Selenium Grid allows us to manage our resources in a very efficient manner. Suppose you have one resource on the system, and the other resources are on a remote site. You can still manage them accordingly and execute the testing process with the same efficiency.


  • In Selenium Grid, the testing scripts get executed on the local machine where the testing is launched. However, these remote machines are able to receive only control commands from mobile devices/browsers. Due to this, we get an issue in uploading/downloading the resource files.
  • The efficiency of Selenium Grid degrades if there are a huge amount of nodes.
  • There is a need for significant time and practice in the initial phase of distributed testing. If the parallel testing setup is not organized before, the overall result may be degraded.

Distributed Test Execution using Selenium Grid

Distributed testing execution for cross-browser testing is the process of testing for compatibility across multiple systems. When the software company releases an update of software very frequently in Agile projects, the organization needs to execute the testing process in a distributed manner. Using the distributed test execution for cross-browser testing increases the efficiency of the project and reduces the test execution time. Distributed testing using Selenium Grid helps to organize your test against various web browsers and operating systems using remote machines and systems.

Consider working on a big project with quick iterations and having to run more than 500 automated tests. Depending on the exam type, even high-performance tests may require up to eight hours to complete their tasks. The testing process cannot be delayed for hours by the development team. If we add five more servers and conduct the tests in parallel, we can implement distributed testing in this situation and reduce testing time to one hour. To perform distributed testing efficiently, the tester needs to follow some rules and conditions, which are as follows:

  • All the shared resources to execute the distributed test should be managed and operated in a proper manner. One Of the most frequently shared resources in the case of distributed systems is the file manager. This factor is essential as it contains the field that is needed during the execution of a testing process. Also, it manages the uploading and downloading of the files during the testing process.
  • There should be one test stand where you can separate all the data usage that is being used during cross-browser testing. Make sure that each iteration of the testing process uses its own separate data so that any interference with the other test can be avoided.
  • Lastly, always keep in mind that the test, having environment configuration changes, should not be executed in parallel with other tests because it may lead to inconsistency and will affect the result of the distributed test execution for cross-browser testing.


Selenium Grid is an open-source tool that is used to perform cross-browser testing for websites and web applications against many operating systems and parallel browsers. There are mainly two components of Selenium Grid which are Hub and Nodes. Hub is the central repository of the tool, and nodes are the individual machines that perform the testing process. It saves time to execute the distributed testing technique.

The saved time can be used for other purposes of the organization. There are many tools available for testing cross-browser compatibility, but Selenium Grid is popular due to its cross-platform compatibility and support of parallel test execution. Hope you have a good understanding of why Selenium Grid is the best choice for distributed execution of tests for faster feedback.


Most Popular