What is Selenium?
Selenium is just one of the automated testing suites that are most popular. Selenium was created in a way to support and motivate automation testing of practical facets of web based applications along with a wide array of platforms and browsers. Owing to its existence in the open source community, it's become among the most tools that are accepted amongst the testing experts.
 
Selenium isn't just a utility or one program, rather a program of several screening tools as well as for the same reason it is known as a Suite. Each of these tools is designed to cater different testing and test environment requirements.
 
The suite program represents of these sets of tools:

Selenium Integrated Development Environment (IDE) - Selenium IDE is a record and playback device. It is distributed as a Firefox Plug-In.

Selenium Remote-Control (RC) - Selenium RC is a host which allows user to make test scripts in a programming language that is desired. In addition, it enables executing test scripts within the big spectrum of browsers.

Selenium WebDriver - WebDriver is a different tool altogether that has numerous advantages over Selenium RC. WebDriver immediately communicates with the browser and uses its indigenous compatibility to automate.

Selenium Grid - Selenium Grid is used to role out your test execution on environments and multiple systems concurrently.
 
Features of Selenium:
  • Selenium is free and open source.
  • Have supporting communities and a sizable user base.
  • have Cross-Browser compatibility (Firefox, chrome, Ie, Safari etc.).
  • have excellent platform compatibility (Windows, Mac OS, Linux etc.).
  • supports numerous programming languages (Java, C#, Ruby, Python, Pearl etc.).
  • Has routine and clean developments.
  • supports dispersed screening.