Text & Dev Tools

Regex Tester & Explainer

Test regular expressions with live match highlighting, capture group breakdown, and plain-English explanations.

/ /
Examples:
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Matches
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Groups
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Flags
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Matches

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Plain-English Explanation

Explanation will appear here...

Quick Reference Cheat Sheet

Anchors

^ Start of string
$ End of string
\b Word boundary
\B Non-word boundary

Quantifiers

* 0 or more
+ 1 or more
? 0 or 1
{n} Exactly n
{n,m} Between n and m

Character Classes

. Any character
\d Digit [0-9]
\w Word char [a-zA-Z0-9_]
\s Whitespace
[abc] Character set
[^abc] Negated set

Groups

(abc) Capture group
(?:abc) Non-capture group
(?<name>abc) Named group
a|b Alternation

Lookaround

(?=abc) Lookahead
(?!abc) Neg. lookahead
(?<=abc) Lookbehind
(?<!abc) Neg. lookbehind

Flags

g Global (all matches)
i Case-insensitive
m Multiline (^ $ per line)
s Dotall (. matches \n)
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Frequently Asked Questions

Is this regex tester free?
Yes, completely free with no signup or account required.
Which regex flavor does this tool use?
It uses JavaScript's built-in RegExp engine, which supports most common regex syntax including lookaheads, lookbehinds, named groups, and Unicode properties.
Is my data sent to a server?
No. All regex matching happens entirely in your browser. Your patterns and test strings never leave your device.