Just a basic regular expression tester. Shows capture groups and highlights matches. Many more features to come in future updates including bookmarked expressions, bookmarked search text, in-app documentation, shortcut keys, special matching options, and opening external files. Developed this simple app because there were no free apps supporting realtime match updates in the app store. Please write to me if you would like this to have more features, or are interested in working on this as an open-source project.