Silk Test is a commercial testing tool developed by Micro Focus for testing web and mobile applications. It provides a range of features for creating and executing automated test cases, including support for a variety of programming languages and the ability to test applications on different platforms and devices.  Selenium is an open-source testing tool for testing web applications. It consists of a suite of tools, including the Selenium WebDriver, which allows you to write automated tests in a variety of programming languages and run them against any web browser that supports JavaScript. Selenium also has a wide range of community support and plugins available for extending its functionality.  One major difference between Silk Test and Selenium is that Silk Test is a commercial tool and is therefore not free to use. Selenium, on the other hand, is open source and freely available for anyone to use.  Another difference is that Silk Test has a more comprehensive feature set and is generally considered to be more powerful than Selenium. However, Selenium is often preferred by developers because it is open source and has a larger user base and community support.  Overall, the choice between Silk Test and Selenium will depend on your specific needs and budget. If you are looking for a commercial testing tool with a wide range of features, Silk Test might be a good option. If you are looking for a free, open-source tool with a strong developer community, Selenium might be a better choice.