JavaScript Regex Tester
Test JavaScript regular expressions, flags, matches, captures, and replacements locally.
Enter a JavaScript pattern without / delimiters.
Optional. Uses JavaScript String.replace semantics.
Examples
Pattern, flags, test text, and replacement stay in this browser. Nothing is uploaded or saved.
A regex match is not proof that data is valid, safe, authorized, or suitable for identity verification.
Set a pattern and test text, then run the pattern.
Replacement preview
—Quick reference
Common tokens
.- Any character except line terminators
\d / \D- Digit / non-digit
\w / \W- Word character / non-word character
\s / \S- Whitespace / non-whitespace
^ / $- Start / end of input or line with m
* + ? {n,m}- Quantifiers
(...) / (?:...)- Capturing / non-capturing group
(?<name>...)- Named capture
\k<name>- Named backreference
(?=...) / (?<=...)- Lookahead / lookbehind
\p{L}- Unicode property; use u or v
JavaScript flags
d- Indices
g- Global
i- Ignore case
m- Multiline
s- Dot all
u- Unicode
v- Unicode sets
y- Sticky
How to use this tool
Enter a JavaScript pattern without delimiters, select only the flags your runtime uses, test with disposable text, and inspect capture ranges before copying a result.
When not to use it
A match is not validation, authorization, or proof that identity, security, or untrusted input is safe.