Regex Tester
Test regular expressions with live match highlighting and capture group display.
All processing happens in your browser. No data is sent to any server.
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Test String
Matches (highlighted)
How It Works
The Regex Tester creates a JavaScript RegExp object from your pattern and flags, then executes it against your test string. Each match is highlighted in the text display, and detailed information about each match (including capture groups) is shown below.
Available flags include: g (global - find all matches), i (case-insensitive), m (multiline - ^ and $ match line boundaries), and s (dotAll - dot matches newlines). The tester shows the full match text, its position in the string, and any named or numbered capture groups.
Invalid regex patterns produce a clear error message. All processing runs in your browser using native JavaScript RegExp.