Regex Tester — Live Match Highlighting
Paste a regex pattern and test text — see matches highlighted instantly with alternating colors. View capture groups, match positions, and use replace mode with $1/$2 substitution. No account needed.
Test a RegexNo UploadFiles stay on your device
No SignupNo account required
Runs in BrowserWorks offline too
Free ForeverNo limits, no watermarks
What you get
- ✓Live match highlighting as you type
- ✓Alternating colors for adjacent matches
- ✓All 6 regex flags (g, i, m, s, u, y)
- ✓Match count and index positions
- ✓Named capture group display
- ✓Replace mode with $1/$2 substitution
Frequently asked questions
What regex flavour is used?
JavaScript's native RegExp engine — the same one that runs in your browser. Supports all ES2024 features including named groups, lookbehind, and the dotall (s) flag.
Can I use replace with capture groups?
Yes. Switch to Replace mode and use $1, $2, etc. for numbered groups, or $<name> for named groups in your replacement string.
Free · No account · No upload · Works offline