Test, debug, and explain regular expressions in real time with match highlighting and capture-group breakdowns.
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Flags:
Test String
Enter a regex and test string to see matches
Enter a regex to see explanation
Replacement string (supports $1, $2, $&, etc.)
Result
How to Use the Regex Tester
Type your regular expression pattern in the input field and enter a test string below. Matches are highlighted in real time as you type. Toggle flags like global (g), case-insensitive (i), multiline (m), dotall (s), unicode (u), and sticky (y) to change matching behavior. View detailed match results, a human-readable explanation of your regex, live find-and-replace, and generated code snippets for six programming languages.
Features
Real-time match highlighting with colored overlays. Detailed match list with capture groups and named groups. Human-readable regex explanation that breaks down every token. Live substitution preview with backreference support ($1, $2, $&). Code generation for JavaScript, Python, Java, C#, PHP, and Go. Built-in quick reference cheat sheet. All processing happens in your browser  nothing is sent to a server.