Regex Tester Online Free
Test and debug regular expressions with live match highlighting. Includes Indian patterns (PAN, mobile, PIN).
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About Regex Tester & Debugger Online
Test and debug regular expressions in real time with live match highlighting. Includes pre-built patterns for Indian mobile numbers, PAN cards, email, PIN codes, URLs and more.
Regular expressions are notoriously easy to get subtly wrong — a pattern that matches your three test cases can still fail on edge cases you didn't think to check, and debugging a broken regex by eye in raw code is slow and error-prone. Real-time visual match highlighting solves this by showing exactly which parts of your test string match as you type the pattern, making it immediately obvious when a pattern is too greedy, too narrow, or matching the wrong groups. This tool includes common pre-built patterns (email, URL, phone number, IP address) as starting points and supports the standard regex flags, making it useful both for writing new patterns and for understanding what an unfamiliar regex from someone else's code is actually doing.
How to use
- Paste or type your input directly into the editor — output updates in real time as you work.
- Check the error/status indicator if your input is invalid; it points to the exact line or issue where relevant.
- Use the copy or download button to grab the processed output once it looks right.
- Chain into a related tool below if your workflow needs a second processing step.
- Processing happens entirely client-side in your browser — nothing you paste is uploaded to a server.
Tool details
⚡ Next step — complete your workflow
Frequently asked questions
What regex flags are available?
g (global), i (case-insensitive), m (multiline), s (dotall), u (unicode). Most common: gi for global case-insensitive search.
Regex for Indian mobile number?
/[6-9]\d{9}/ matches valid Indian mobile numbers starting with 6, 7, 8, or 9 followed by 9 digits.
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