Regex Tester
Test, explain, and debug regular expressions with syntax highlighting, explanation panel, quick reference, and live match preview.
Enter a regex pattern to see explanation and matches
Explanation
gglobal — find all matches, not just the firstQuick Reference
Character Classes
\ddigit (0-9)\wword char (a-z, A-Z, 0-9, _)\swhitespace (space, tab, newline).any character except \n\D \W \Sinverse of \d \w \sQuantifiers
*0 or more (greedy)+1 or more (greedy)?0 or 1 (greedy){n}exactly n times{n,m}n to m times{n,}n or more times*? +?lazy (non-greedy) versionsGroups & Lookaround
(...)capture group — stores match in $1, $2...(?:...)non-capturing group — no backreference(?<name>...)named group — access by name(?=...)positive lookahead(?!...)negative lookahead(?<=...)positive lookbehind(?<!...)negative lookbehindAnchors & Boundaries
^start of string (or line w/ m flag)$end of string (or line w/ m flag)\bword boundary\Bnon-word boundaryAlternation & Misc
|OR — match left or right side\escape next character[...]character set — match any inside[^...]negated set — match anything NOT insideShorthand Examples
\d{3}-\d{4}phone pattern (3 digits — 4 digits)\w+@\w+\.\w+simple email patternhttps?://.*URL starting with http(s)^[A-Z][a-z]+$capitalized word (full line)Online Regex Tester & Explainer
Write, test, and understand regular expressions with live visual feedback. The pattern input supports syntax highlighting: character classes appear in blue, quantifiers in green, anchors in red, groups in purple, and alternation in orange. A token bar below the input mirrors the breakdown, and hovering any token (or its matching explanation row) highlights both in yellow for quick cross-referencing.
The right sidebar contains a detailed Explanation panel that translates each part of your regex into plain English, plus a searchable Quick Reference covering character classes, quantifiers, groups, lookaround assertions, anchors, and common shorthand patterns. Supports all JavaScript regex features: lookahead/lookbehind assertions, named groups, Unicode property escapes, and dotAll mode.
Switch to Replace mode to test substitutions with $1/$2 backreferences and see a live preview. All processing happens locally in your browser — no data is ever uploaded to a server.