Regex Tester & Debugger
Test, debug, and understand your Regular Expressions in real-time with syntax highlighting.
The Regex Tester is an advanced tool for writing and debugging Regular Expressions directly in your browser. It evaluates your patterns against a test string in real-time, instantly highlighting successful matches. Whether you are validating email formats, extracting data, or learning regex fundamentals, this visual interface makes the complex syntax understandable. Included below the tester is a handy cheat sheet of common regex tokens.
How to use Regex Tester & Debugger
1
Write Pattern: Enter your regex pattern in the top input field.
2
Set Flags: Add optional flags like 'g' (global) or 'i' (case-insensitive) in the flags field.
3
Test String: Provide a sample text below; matches will be automatically highlighted in green.
Frequently Asked Questions
What regex engine is used?
The tool uses the native JavaScript Regular Expression engine.
Why isn't my pattern matching multiple times?
Make sure you include the 'g' (global) flag in the flags input box.
Are lookbehinds supported?
Yes, modern JavaScript engines support lookaheads and lookbehinds, so they will work here.
Is my text data secure?
Absolutely. All regex processing occurs securely on your local device.
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