/./ Regex Tester
Enter a regular expression and test string to see matches highlighted in real time. Capture groups are displayed below. Use the pattern library for common regex snippets.
FAQ
What regex flavour does this use?
This tool uses JavaScript's built-in RegExp engine, which supports ECMAScript regular expressions. This includes features like lookahead, lookbehind (in modern browsers), named groups, and Unicode property escapes.
What are regex flags?
g (global) finds all matches; i (case-insensitive) ignores case; m (multiline) makes ^ and $ match line boundaries; s (dotAll) makes . match newlines; u (unicode) enables Unicode matching.
How do capture groups work?
Parentheses () in your regex create capture groups. Each group captures the matched substring separately. Named groups use (?<name>...) syntax. Groups are shown in the "Groups" panel below the matches.