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Regex Tester

Online regex tester with live highlighting, capture groups, and replacement preview. Test JavaScript regular expressions safely in your browser with a quick reference cheatsheet.

Pattern

Flags

Test string

Matches (3)

Match details

[email protected]at index 14

[email protected]at index 38

[email protected]at index 67

Replace preview

Contact us at [redacted] or [redacted].
Backup: [redacted]
Invalid: not-an-email

Regex cheatsheet

Character classes

. — any char except newline
\d / \D — digit / non-digit
\w / \W — word / non-word
\s / \S — whitespace / non-whitespace
[abc] — any of a, b, c
[^abc] — none of a, b, c

Quantifiers & anchors

* — 0 or more
+ — 1 or more
? — 0 or 1
{n,m} — between n and m
^ / $ — start / end of line
\b — word boundary

Groups

(abc) — capture group
(?:abc) — non-capture group
(?<name>abc) — named group
a|b — alternation

Flags

g — global, find all matches
i — case-insensitive
m — multiline anchors
s — dot matches newline
u — full unicode

Patterns you can copy

Email: ^[\w.+-]+@[\w-]+\.[\w.-]+$
URL: https?:\/\/[\w.-]+(?:\/[\w./?%&=-]*)?
IPv4: \b(?:\d{1,3}\.){3}\d{1,3}\b
Hex color: #(?:[0-9a-fA-F]{3}){1,2}\b
UUID: [0-9a-f]{8}-(?:[0-9a-f]{4}-){3}[0-9a-f]{12}