🔍 Regex Tester

Regex Tester online free. Test regular expressions in real time with match highlighting. Supports JavaScript regex. Flags: global, case insensitive, multiline. With cheat sheet.

🔒 100% Free · No Login · Works in Browser

About Regex Tester

Regular expressions (regex) are powerful patterns used to search, match, and manipulate text. They are used in programming for form validation, text parsing, search and replace operations, and data extraction. Writing correct regex can be tricky — our tester lets you test and refine patterns instantly with real-time match highlighting.

IHAVEALL Regex Tester uses JavaScript's built-in RegExp engine which is the same regex engine used in Node.js, browsers, and most JavaScript frameworks. Test your patterns against sample text and see all matches highlighted in real time as you type. Perfect for developers building input validation, data parsers, or text processing scripts.

Common Regex Use Cases

Email validation, phone number format validation, extracting dates from text, finding duplicate words, validating credit card numbers, parsing log files, extracting URLs from text, validating passwords for complexity requirements, and cleaning up data in CSV files.

📖 How to Use

Open the Tool

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Enter Your Data

Input your text, file, or values

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❓ Frequently Asked Questions

What regex flags are supported?+

The tester supports all standard JavaScript regex flags: g (global — find all matches), i (case insensitive), m (multiline — ^ and $ match line boundaries), and s (dotAll — dot matches newlines).

How do I match an email address with regex?+

A basic email regex pattern is: [a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,} This matches most standard email formats but email validation is complex — consider using HTML5 input type email for forms.

What is the difference between * and + in regex?+

The asterisk * matches zero or more occurrences. The plus + matches one or more occurrences. So a* matches even an empty string while a+ requires at least one letter a.

How do I match a specific number of characters?+

Use curly braces for exact counts. {3} means exactly 3. {2,5} means between 2 and 5. {3,} means 3 or more. Example: [0-9]{10} matches exactly 10 digits like an Indian phone number.

Why does my regex match too much?+

You may need to use anchors or word boundaries. ^ anchors to start of string, $ anchors to end, matches word boundaries. Also consider using non-greedy quantifiers *? and +? to match the shortest possible string.