Regex Pattern Tester
Enter any regex pattern with custom flags (g, i, m, s), paste a test string, and instantly see all matches highlighted inline with their positions and capture groups. Pre-loaded with an email extraction demo. Supports all JavaScript regex features.
The Challenge
Safely executing user-provided regex patterns in real-time without catastrophic backtracking crashes or infinite loops, while rendering highlighted matches inline with the original text.
The Approach
Created a sandboxed RegExp executor with match-count safety limits. Highlighted matches are generated by splitting the test string at match boundaries and rendering alternating styled spans. All flags are user-configurable.
The Result
A real-time regex debugger that eliminates trial-and-error regex development — instant visual feedback on every pattern change.