Regex Tester — Test Regular Expressions with Match Highlighting
Test regular expressions against sample text and see every match highlighted with its position and capture groups. Validate your patterns before using them in code. Uses the JavaScript regex engine and supports the flags global (g), case-insensitive (i), multiline (m), dotAll (s), unicode (u) and sticky (y).
ECMAScript Client-Side Only
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Features
- Pattern matching with highlighted results
- Flags g, i, m, s, u and y
- Match highlighting with capture groups
- Detailed match information and statistics
- Copy and download match results
- 100% client-side processing
Regular Expression Testing
- JavaScript Engine: This tool uses JavaScript's RegExp engine for pattern testing
- Run on demand: click Test or press Enter (Ctrl+Enter in the test string) to see matches highlighted
- Privacy: All testing happens locally in your browser - no data is sent to servers
Useful Resources
Wikipedia: Regular Expression Beginner-friendly introduction to regular expressions
MDN Regular Expressions Guide Comprehensive guide to regular expressions in JavaScript by Mozilla
Regular-Expressions.info In-depth tutorial and reference for regex patterns and syntax
RegExr - Community Patterns Learn regex with thousands of community-contributed patterns
Regex101 - Testing & Debugger Advanced regex testing with explanation and visualization