Regex Tester
PopularTest regular expressions with live highlighting
About Regex Tester
Regex Tester & Debugger allows developers to write, test, and refine regular expression patterns against sample text in real time. It features match highlighting, group capturing, and regex flag controls (global, case-insensitive, multiline).
Perfect for validating email formats, phone numbers, log patterns, and data extraction rules without needing to restart code compilers.
Common Use Cases
- Testing email, phone number, and password validation patterns for web forms
- Extracting IP addresses, timestamps, or error codes from server log files
- Debugging complex search-and-replace patterns for text processing scripts
How to Use Regex Tester
- Enter your Regular Expression pattern (e.g. `[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}`).
- Set regex flags (g: global, i: ignore case, m: multiline).
- Type or paste sample text to see instant match highlights and captured groups.
Real-World Examples
Contact support@sajilotools.com for assistance.Match 1: support@sajilotools.com (Index 8-31)Important Notes & Limitations
- Uses JavaScript RegExp engine syntax rules (ECMAScript specification)
Privacy & Data Security
Regex Tester processes all operations 100% locally in your web browser memory. Your files, text snippets, and generated outputs are never stored, logged, or uploaded to any remote server.
Frequently Asked Questions
It uses JavaScript's native ECMAScript RegExp engine, matching exact browser runtime regex behavior.
Yes, you can toggle Global (g), Case-Insensitive (i), Multiline (m), and Unicode (u) flags directly in the control panel.
Yes, matched groups and parenthesized sub-matches are listed with indexes for debugging.
You can test thousands of lines of log data directly in your browser without performance degradation.