Regex Tester

Test regular expressions with real-time match highlighting, group capture display, and a pattern library.

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1. Enter your regular expression pattern in the regex input field at the top. 2. Toggle the desired flags (global, case-insensitive, multiline, etc.) using the flag buttons. 3. Paste or type your test string in the text area below to see matches highlighted in real time. 4. Review the match results panel showing matched text, capture groups, and index positions. 5. Browse the built-in pattern library to load common regex patterns like email or URL validation. 6. Copy your finalized regex pattern for use in your application code.

About This Tool

The Regex Tester provides a powerful environment for writing, testing, and debugging regular expressions with instant visual feedback. Type your pattern and test string, and matches are highlighted in real time - including individual capture groups displayed with color coding and detailed match information.

The built-in pattern library offers dozens of ready-made regex patterns for common tasks like email validation, phone numbers, URLs, IP addresses, dates, and more. Select a pattern from the library to load it instantly, then customize it for your specific needs. Each pattern includes an explanation of how it works.

Supporting all JavaScript regex flags (global, case-insensitive, multiline, dotAll, unicode, sticky), this tool also shows the match index, captured groups with names, and a plain-English explanation of what your pattern does. It is an essential companion for any developer working with text processing, form validation, or data extraction.

Frequently Asked Questions

This tester uses the JavaScript (ECMAScript) regex engine, which is the same engine used in all modern browsers and Node.js. Patterns are tested using the native RegExp object for accurate results.
Yes. Each capture group is highlighted with a distinct color in the test string, and the matched content for each group is displayed in a detailed results panel. Named capture groups are shown with their names.
All JavaScript regex flags are supported: g (global), i (case-insensitive), m (multiline), s (dotAll), u (unicode), and y (sticky). You can toggle each flag independently.
Yes. The library includes patterns for email addresses, URLs, phone numbers, IP addresses (v4 and v6), dates in various formats, credit card numbers, postal codes, strong passwords, and many more common use cases.
JavaScript regex syntax is largely compatible with other languages, but there are differences. Features like lookbehind assertions and Unicode property escapes vary between engines. This tool is most accurate for JavaScript, TypeScript, and similar environments.

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