Selenium vs Galen: What are the differences?
Developers describe Selenium as "Web Browser Automation". Selenium automates browsers. That's it! What you do with that power is entirely up to you. Primarily, it is for automating web applications for testing purposes, but is certainly not limited to just that. Boring web-based administration tasks can (and should!) also be automated as well. On the other hand, Galen is detailed as "Automated testing of responsive design and html layout for web applications". It is a tool for testing layout of responsive web apps. It is based on Selenium and has a special language for testing page layout.
Selenium and Galen can be categorized as "Browser Testing" tools.
Selenium and Galen are both open source tools. Selenium with 15.3K GitHub stars and 5.05K forks on GitHub appears to be more popular than Galen with 1.33K GitHub stars and 143 GitHub forks.