Selenium IDE is a browser extension that simplifies the process of creating automated tests for web applications, allowing users to record their actions and playback them without writing code. It provides a user-friendly interface to create test cases directly within the browser, making it ideal for accelerating repetitive tasks. The tool offers various features, including control flow commands, assertions, and pause functionality, which enable users to refine recorded scripts and handle dynamic content. By using Selenium IDE, users can automate tests without extensive coding knowledge, making it a popular choice for beginners and experienced testers alike.