JavaScript Regular Expressions Visualizer

Explore the power of regex patterns.

Live Regex Tester

Enter a regular expression and a string to see what matches.

Matches

Capturing Groups:

    Key Regex Concepts

    // Capturing Group & Backreference
/(hi)\s\1/  // Matches "hi hi"

// Named Capturing Group & Backreference
/(?<word>hi)\s\k<word>/  // Matches "hi hi"

// Character Class & Quantifier
/[a-zA-Z]+/ // Matches one or more letters

// Lookahead & Lookbehind
/\w+(?=,)/  // Matches a word only if followed by a comma

    Below are more examples of common patterns and what they match.

    `/\bcat\b/` (Word Boundary)

    Matches: `The cat sat.` -> `cat`

    Does NOT Match: `category`

    `/[^aeiouAEIOU]/g` (Negated Character Class)

    Matches: `JavaScript` -> `J, v, s, c, r, p, t`

    `/(?=.*[a-z])(?=.*[A-Z])(?=.*\d).{8,}/` (Lookaheads & Quantifier)

    Checks if a string has at least one lowercase letter, one uppercase letter, one digit, and is 8 characters or more. `Password123` would match.