Interactive JavaScript Regex Tester & Debugger
Debug and refine JavaScript regular expressions in real time. Features live visual match highlighting, flag toggles (g, i, m, s, u), named capture group extraction, and regex replacement simulation.
Key Technical Capabilities
- Detailed Capture Group VisualizerBreaks down matched substrings by index, length, and named group keys.
- Live Replace ModeSimulate string replacement patterns with $1 backreferences and function substitutions.
How to Test Regular Expressions Online
- Enter Regex PatternType your pattern and select flags like global (g) or case-insensitive (i).
- Enter Test StringPaste the target text to see live match highlighting and group breakdowns.
Frequently Asked Questions
- Does this use browser native RegExp engine?
- Yes, tests run directly on the V8 / SpiderMonkey JavaScript engine in your browser.