Selenium:
Selenium is an open-source tool and libraries that is used for browser automation.
Selenium used to allows user to test their websites functionally on different browsers and perform cross browser testing to check if the website functions consistently across different browsers.
It enables testers to write automated tests in various programming languages(like Javascript, Python, Ruby, Java, Kotlin & C#) to test the functionality of web applications.

Components of Selenium

1. Selenium Webdriver
2. Selenium IDE
3. Selenium GRID
4. Selenium RC

Selenium Webdriver
It is a web framework that permits you to execute cross-browser test.
This tool is used for automating web-based application testing to verify that it performs expectedly.
It allows to choose a programming language to create test scripts.
It is more powerful and flexible at a higher cose.

IDE:Integrated Development Element

 It is primarily a record/run tool that a test case developer uses to develop selenium test cases
 It offers simple installation and it is easy to learn.
 It does not require any programming logic to write its test scripts.

Selenium GRID

 Selenium grid is a smart proxy server that makes it easy to run tests in parallel across multiple machines and browsers simultaneously.
 It is done by routing commands to remote web browser instances, where one server acts as the hub.

Advantages of Selenium

 Cross browser testing, work on multiple browser like Chrome, Internet explore, Mozilla firefox, microsoft edge, Safari, etc,.
 Platform independent like windows, Linux, Mac.
 Language support like Javascript, Python, Ruby, Java, Kotlin & C#.
 Flexibility
 Jenkins, Git & Appium.

Jenkins
It is like a different cloud machine and remote testing tool.

Git
It acts as same as Jenkins
It is like CICD(continuous Integration & Continuous Development) pipeline.

Appium
It acts as a server/assistance between selenium script /tablet/android machine.

Disadvantages of Selenium

• Limited support for desktop applications
• Maintenance efforts for test scripts
• Limited support for mobile testing
• Dependency on browser updates
• No support for image-based testing
• Dependency on browser automation