Regex Tester

Build and test regular expressions with live highlighting and match details. Everything runs in your browser -- nothing is uploaded to any server.

100% Private Instant No Limits

Test String

Character Classes

.Any character

\dDigit [0-9]

\wWord [a-zA-Z0-9_]

\sWhitespace

\D \W \SNegated versions

Quantifiers

*0 or more

+1 or more

?0 or 1

{n}Exactly n

{n,m}Between n and m

Anchors & Groups

^Start of string

$End of string

\bWord boundary

(abc)Capture group

(?:abc)Non-capture group

Common Patterns

[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}Email

https?://[^\s]+URL

\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}IPv4

#?([a-fA-F0-9]{6}|[a-fA-F0-9]{3})Hex color

How It Works

Write Your Pattern

Enter a regex pattern in the input bar. Toggle flags like global (g), case-insensitive (i), and multiline (m) with a click.

See Live Matches

Type or paste a test string and see matches highlighted in real time. Alternating colors distinguish adjacent matches.

Inspect Details

The match table shows every match value, position index, and capture groups. Click reference patterns to load them instantly.

Frequently Asked Questions

This tool uses JavaScript's built-in RegExp engine, which follows the ECMAScript specification. It supports all standard features including lookaheads, lookbehinds (ES2018+), named groups, and the Unicode flag. This is the same engine used in Node.js and all major browsers.

No. All pattern matching happens entirely in your browser. Your test strings and patterns never leave your device and are never logged or stored anywhere.

g (global) finds all matches instead of stopping at the first. i (case-insensitive) ignores letter case. m (multiline) makes ^ and $ match line starts/ends. s (dotall) makes . match newlines. u (unicode) enables full Unicode matching.