What is Selenium? Why Use it for Automation Testing?

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What is Selenium? Why Use it for Automation Testing?

Sameeksha Medewar
Last updated on April 16, 2024

    Testing is an indispensable part of the software development process. It ensures that the software works without any errors and meets the expected quality standards. In general, a tested software or application is reliable and secure. Manual and automation testing are the two different types of software testing. This article will give you a brief understanding of the Selenium testing framework.

    In manual testing, the Quality Assurance (QA) team executes tests manually and discovers defects or bugs in the application under development. On the other hand, automation testing involves automation tools that automatically execute test scripts and generate results without human intervention.

    Automation testing saves time and effort and boosts test coverage and execution speed. A plethora of automated software testing frameworks is available out there, including the automated testing suite.

    This article will introduce you to Selenium, which is one of the most popular automated testing frameworks. Also, you will get to know how the automated testing platform was developed and who are its major contributors. Later, we shall discuss the major features, different components, and limitations of the popular testing tool.

    What is Selenium?

    Selenium is a widely used automated testing framework that can automate tests for web applications across different browsers and platforms. Released under the Apache License 2.0 , The automated test framework is open-source and is compatible with Windows, macOS, and Linux.

    It offers a playback tool called Selenium IDE for writing functional tests without the need to learn test scripting language. It uses a domain-specific language known as Selenese for creating functional tests in different programming languages, like Java, Perl, PHP, Python, JavaScript, Groovy, C#, Ruby, and Scala.

    While working with the popular testing framework, you need to know that it is a suite of tools and not a single tool. It consists of four different tools, namely Selenium IDE, Selenium RC, Selenium Grid, and Web Driver. Presently, RC and WebDriver are combined into a single framework to form Selenium 2. Each tool in the testing suite is designed to satisfy different testing needs. Testing web applications using the framework is called Selenium testing.

    Who Developed Selenium?

    There are different developers of Selenium, as it is a collection of different software tools. Following are some of the key contributors to the development of the popular test automation framework.

    Jason Huggins, an engineer at Thoughtworks, primarily created Selenium in 2004. He realized that performing manual testing repetitively was extremely inefficient while working on a web application that needed repeated testing. Therefore, with the need to avoid repetitive manual testing, he developed a JavaScript program named JavaScriptTestRunner. It automatically controlled a browser’s actions.

    Later, he made this program open-source and named it Selenium Core. But it had a major downside. It required users to install the web server and the application under test on their local systems due to the same-origin policy. The policy did not allow JavaScript code to access elements from other domains except the one where it is launched.

    Development of Selenium Remote Control (RC)

    To overcome the issue of the same-origin policy, Paul Hammant developed a server that tricked the browser into believing that the web application under the test and the web server are from the same domain. He named that server Selenium Remote Control or Selenium1.

    Development of Selenium Grid

    Patrick Lightbody developed Grid to reduce the test execution time as much as possible. Initially, he named it Hosted QA. This system uses a distributed environment to execute multiple tests simultaneously.

    Development of Selenium IDE

    Shinya Kasatani from Japan is the developer of Selenium IDE. He incorporated a record-and-playback feature in the testing tool that allows people with little to no coding skills to develop UI tests. The primary idea behind record-and-playback is to let users record their actions while interacting with an application and replay them whenever required.

    Development of Selenium WebDriver

    In 2006, Simon Stewart developed WebDriver, the first cross-platform testing framework that controlled the browser from the OS level. In 2009, RC and WebDriver were merged to form Selenium 2.0.

    What's in the Name?

    During the development of Selenium, an automated testing framework from a company called Mercury Interactive was quite popular. Once Jason Huggings cracked a joke saying that you can cure Mercury poisoning by consuming Selenium supplements. And hence, all developers decided to name their project as such.

    Features of Selenium

    It is one of the most popular automated browser frameworks due to its incredible features. Following are some of the significant features of Selenium:

    1. The testing framework supports all major browsers, such as Safari, Google Chrome, Opera, Edge, Internet Explorer, and Firefox.
    2. It supports multiple programming languages, including Python, Ruby, JavaScript, Perl, and PHP for developing tests.
    3. The automated test platform provides a record-and-playback feature that does not require you to learn test scripting language to write test scripts.
    4. It can seamlessly integrate with other testing frameworks, like TestNG.
    5. Selenium IDE does not require server installation as it directly interacts with the browser.
    6. The commands are easy to learn and implement.
    7. It is a cross-platform framework available for Windows, macOS, Linux, Android, iOS, and Solaris systems.

    Selenium Suite

    Following are the four different tools in the Selenium suite:

    1. IDE

    It is an integrated development environment and primarily a record-and-playback tool for running test scripts. You can add Selenium IDE as an extension to Firefox or Google Chrome browsers. Therefore, it does not require any additional setup. Moreover, it enables you to record, edit, and debug functional tests.


    • A command-line runner can execute tests on any browser/OS combination in parallel.
    • It makes test debugging effortless by allowing users to set breakpoints and pause on exceptions.
    • The run command allows reusing one test case in another.
    • You can extend the functionality of the IDE as it supports plugins.

    2. Grid

    It is one of the most robust components in the automated test suite. Grid allows multiple tests to run parallelly across several machines. It executes WebDriver scripts in remotely located real or virtual machines. When a client sends commands, it routes them to remote browser instances.


    • It facilitates cross-platform testing
    • Supports load balancing
    • Makes it easy to scale tests
    • Provides a central point for all tests

    Selenium Grid uses hubs and nodes for running tests. There can be only one hub and multiple nodes. A hub acts as a local machine or a central point where a client submits tests, and later, it distributes all tests to multiple hubs. Hubs are Selenium instances that execute tests assigned by the hub.

    3. Remote Control

    Selenium Remote Control was the first component of the test framework suite written in Java. It accepts commands via HTTP for the browser. In addition, it allows authoring automated test scripts in any programming language for a web application, which makes the integration of the testing tool with existing unit test frameworks better.

    Running test scripts in RC requires it to install a server, which acts as a mediator between Selenium commands and a browser. Following are the operations that take place when test scripts are executed in it:

    • Initially, the RC server injects Selenium Core into the browser.
    • After that, the RC server sends instructions to Core depending upon the test scripts. The Core runs all instructions from the server as JavaScript commands.
    • Finally, Selenium Core sends those instructions to the web browser. The web browser executes them and sends back the results to the server.

    4. WebDriver

    Selenium WebDriver is one of the most significant components of the testing suite and a successor of Selenium Remote Control. It accepts commands from a client or API or commands sent in Selenese language. A browser-specific browser driver sends those commands to the browser and gets back the results.

    Unlike RC, there is no need for a server installation for executing tests in WebDriver. Instead, it directly starts with a browser instance and controls it. You can use WebDriver with Grid to run tests on remote systems.

    Limitations of Selenium

    Some significant limitations of the popular automated testing framework are listed below:

    • It only supports the automation testing of web applications.
    • Its results are not accurate while testing dynamic web pages.
    • Selenium does not have a built-in reporting feature and depends on other frameworks, like TestNG and Cucumber.
    • It does not automate barcodes and captchas.
    • The test framework is not capable of handling pop-ups and frames efficiently.
    • You cannot use the popular testing framework for testing images and performing automation analysis on SOAP or REST web services.
    • The automated testing suite experiences enormous page load, timeout, and sync issues.
    • It does not support test management tasks.


    Selenium is one of the best automation testing tools that automate web browser interactions. It enables you to write automated test scripts for web applications in any of its supported languages. Moreover, it offers a wide variety of features that are better than most automated testing frameworks.

    We hope this article has helped you understand the popular automated testing framework and its different components. With an increased focus on automated testing these days and Selenium being one of the best automation testing frameworks for web applications, learning it would be beneficial to ensure a promising career in software testing.

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    The three components of the Selenium Framework are: Selenium Grid, Selenium WebDriver, and Selenium IDE.

    Selenium IDE is one of the tools of Selenium that lets test case developers create Selenium test cases. It is a beginner-friendly tool from the Selenium test suite for developing test cases for web applications.

    Selenium leverages its own test domain-specific language called Selenese. In addition to it, Selenium supports other programming languages, including Java, Ruby, Python, and C#.

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