What is a regular expression?

A regular expression (regex) is a pattern used to match, search, and manipulate text. They are widely used in programming for validation, parsing, and text processing.

Which regex flavour does this tool use?

This tool uses JavaScript regex syntax (ECMAScript), which is compatible with Node.js, browser JavaScript, and most modern languages.

What regex flags are supported?

g (global), i (case insensitive), m (multiline), s (dotAll), and u (unicode) flags are supported.

Regex Tester — Test Regular Expressions Online Free

Test and debug regular expressions in real time. Enter your pattern and test string to see matches highlighted instantly. Supports JavaScript regex flags. Free, runs in browser.

Regular expression

0ms

i— ignore caseg— globalm— multilines— dotAllu— unicodey— sticky

Active: ig

Test text

Highlighted preview0 matches

Extractor0 groups

Group #

No extracted results yet.

Group 0 = full match · 1+ = capture groups

Replace preview

Replacement string

Type a replacement to preview results.

$& = whole match · $1+ = capture groups

Matches & groups

#	Index	Match	Captures	Named groups
No matches yet.

Flag reference

iCase-insensitive matching

gFind all matches, not just the first

mMake ^ and $ match start/end of each line

sLet . match newline characters (dotAll)

uFull Unicode support

ySticky — match only at lastIndex position

Notes

—Runs entirely in your browser — no data is sent to a server.
—Use the g flag to find all matches; without it only the first match is returned.
—Named groups use the syntax (?<name>…) and appear in the Named groups column.
—The Export CSV button downloads all matches with captures as a spreadsheet-ready file.

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