Regex Shuttle vs RegexAssistant

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.

RegexAssistant has no write-up on Specifiction yet; its figures are above.