Pattern

Flags

📖 Regex cheatsheet

. any char \d digit \w word \s space

\D \W \S negated versions

^ start $ end \b word boundary

* 0+ + 1+ ? 0/1 {2,5} range

*? lazy [abc] set [^abc] negated

(x) group (?:x) non-capturing

(?<name>x) named group \1 backref

x(?=y) lookahead x(?!y) negative

(?<=y)x lookbehind a|b alternation

Flags: g all i case m multiline s dotall u unicode

Common patterns

Test string

Highlighted matches

Match list

How it works

Uses your browser's native RegExp engine — the same one your JavaScript code would use.
Common flags: g (global, find all matches), i (case-insensitive), m (multiline), s (dot matches newline).
Invalid patterns show an error instead of a crash.