Regex Tester
How to Use Regex Tester
1
Enter Pattern & Test String
Type your regular expression and paste the string you want to test against.
2
Toggle Flags
Enable global, case-insensitive, multiline, dotall, unicode, and sticky flags as needed.
3
Review Matches & Replace
See every match highlighted with indices and capture groups, or preview a replace using $1, $2.
Key Features
Real-Time Highlighting
Matches are highlighted in the test string instantly as you type your pattern.
All Six Flags
Full g, i, m, s, u, y flag toggles for JavaScript regular expressions.
Capture Group Table
Every match lists its groups with values and indices for precise debugging.
Replace Mode
Test a replacement string with $1, $2 capture group references and see the output.
JS Literal & 100% Client-Side
Copy the pattern as a ready-to-paste JavaScript literal. Everything runs locally.
Frequently Asked Questions about Regex Tester
The test string is segmented around every match and rendered with highlights, so you can see exactly what matched.