Regex Shuttle vs The Regex Coach

Regex Shuttle is a free browser-based tool for testing, explaining, and learning regular expressions. As users type, it highlights matches and displays match details, groups, and indices. Its explainer separates expressions into tokens and gives plain-English descriptions, while a library provides ready-to-use patterns to copy or open in the tester. A cheat sheet covers regex characters, quantifiers, anchors, groups, and flags. The tool can preview find-and-replace results in real time, including capture-group references such as $1 and $2. It uses JavaScript's built-in RegExp engine, so its behavior follows JavaScript regex behavior in browsers and Node.js. The maker says it supports capturing groups, lookahead and lookbehind assertions, named groups, and Unicode patterns. Regex processing occurs locally in the browser; patterns and test strings are not uploaded, collected, or shared with third parties. The maker says it continues working offline after its first load. No signup or email is required, and the interface is available in English and Chinese. The Free plan is free, with no limits or ads.

The Regex Coach is a graphical application for experimenting interactively with Perl-compatible regular expressions. It shows whether a pattern matches a target string and updates the interface when changes are made. Users can highlight captured groups or selected parts of a pattern in the target text. The application can attempt a plain-English explanation of a regex, show its parse tree graphically, and step through the matching process. It also simulates Perl split and substitution operations. Written in Common Lisp, it uses CL-PPCRE as its regex engine. The current Windows download is version 0.9.2; the maker says the program has not changed since 2008. Linux is no longer maintained, though an unsupported 0.8.5 release is available and also runs on FreeBSD. There is no Mac version planned. The program is provided as-is without warranty, and the maker says not to expect support for older Windows configurations or the unsupported Linux release. The engine may overflow its stack with relatively long regular expressions. The listed plan is free, with conditions for commercial use and redistribution.