Browser-Side Only

Regex Tester & Explainer

Live matching, capture group highlighting, replace mode, pattern explainer, 15 common patterns, and a full cheat sheet. Runs entirely in your browser.

100% private. Your regex and test strings never leave your browser — no server, no logging, no tracking.
Pattern
/ /
Flags
/ /g
Test String
0 matches
Matches
Enter a pattern and test string to see matches.
Regex Explainer
Start typing a pattern to see an explanation of each component.
Quick Actions
Flags guide:
g global — find all   i case-insensitive   m multiline
s dot-all   u unicode   y sticky
Replace tokens:
$1 $2 capture groups   $& whole match   $$ literal $

Common Patterns Library (15 pre-built)

Regex Cheat Sheet