developer tools
Regular Expression Tester
Test, build, and debug complex RegEx patterns in real time with visual match highlighting and capture group inspection.
Evaluated locally inside your browser's JavaScript engine.
//g
Flags:
Match Results (0)
No matches found in the test string.
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How to Use Regex Tester & Cheat Sheet
1
Enter Regex
Type your regular expression pattern and choose flags (g, i, m, s).
2
Provide Test Text
Paste the text you wish to match against.
3
Inspect Matches
View highlighted matches and captured group arrays.
About Regex Tester & Cheat Sheet
Executes client-side `RegExp.prototype.exec()` loops with safety guards against catastrophic backtracking.
Key Features
- Real-time evaluation with interactive match highlighting
- Support for flags: Global (g), Case-Insensitive (i), Multiline (m), DotAll (s)
- Capture group breakdowns
- Built-in regex cheatsheet for common patterns (emails, URLs, phone numbers)
Frequently Asked Questions
It uses modern ECMAScript (JavaScript) RegEx standards, supporting lookaheads, lookbehinds, unicode property escapes, and named capture groups.