Regex Tester
Test regular expressions with real-time match highlighting. Supports flags and capture groups.
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How to Use
- Enter your regular expression pattern in the pattern field (between the
/delimiters). - Toggle flags such as
g(global),i(case-insensitive),m(multiline), ors(dotAll) as needed. - Type or paste your test string — matches are highlighted in real time and capture groups are listed below.
Frequently Asked Questions
- What regex engine does this use?
- This tool uses the built-in JavaScript <code>RegExp</code> engine in your browser, which follows the ECMAScript standard.
- What does the <code>g</code> flag do?
- The global flag makes the engine find all matches instead of stopping after the first one.
- What are capture groups?
- Groups enclosed in parentheses <code>()</code> capture parts of the match. This tool displays each group's value per match in the table below the highlighted output.
- Is my input sent to a server?
- No — all matching and highlighting runs entirely in your browser with no network requests.