Regex Tester Online
Powerful regex tester online. Test, debug, and visualize your regular expressions with real-time highlighting and validation.
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Test String
Match Preview
0 Matches FoundThe quick brown fox jumps over the lazy dog
How to Use Regex Tester
- 1Type or paste your regular expression pattern into the 'Regular Expression' input field.
- 2Add optional flags like 'g' (global) or 'i' (ignore case) in the 'Flags' box.
- 3Enter the text you want to test in the 'Test String' area.
- 4Matches will be highlighted in real-time in the 'Match Preview' panel.
- 5Hover over any highlighted match to see its specific index within the string.
Key Features
- Live Highlighting: See match results instantly as you type your pattern or text.
- Error Validation: Detailed error messages for invalid regex syntax to help you debug.
- Common Presets: Quick-load samples for email, URL, date, and phone number validation.
- Flag Support: Full support for JS regex flags (g, i, m, s, u, y).
- High Privacy: 100% client-side execution; your strings never leave your device.