Regex Tester – Test Regular Expressions Online Free
Test and debug regular expressions with live match highlighting and group capture. Free online regex tester.
Frequently Asked Questions
This tool uses JavaScript's built-in RegExp engine, which follows the ECMAScript regex specification. It supports most common regex features including lookaheads, named groups, and Unicode.
g (global) finds all matches. i makes matching case-insensitive. m makes ^ and $ match line boundaries. s makes . match newlines (dot-all mode).
Wrap parts of your pattern in parentheses, e.g. (\\w+)@(\\w+). Captured groups are shown in the Match Details section.
The tool shows up to 1000 matches to prevent browser slowdowns. Match details are shown for the first 50.
Yes. All regex processing happens in your browser using JavaScript's native RegExp. Nothing is sent to any server.
What is Regex Tester?
A regex tester lets you write and test regular expressions against sample text in real time. Regular expressions are patterns used to match, search, and manipulate text in programming. Our Regex Tester highlights all matches in the test string, shows captured groups, and supports JavaScript regex flags (global, case-insensitive, multiline).
How to Use Regex Tester
- 1Enter your regular expression in the pattern field.
- 2Enter the test string in the text area.
- 3Matches are highlighted in real time.
- 4View captured groups in the results panel.
Key Features
- ✓Real-time match highlighting
- ✓Captured group display
- ✓JavaScript regex flags (g, i, m, s)
- ✓Match count and position display
Benefits
- →Debug complex regular expressions quickly
- →Test patterns before using them in code
- →Learn regex by seeing matches in real time
Why Use Irreva for Regex Tester?
Frequently Asked Questions
What regex flavor does this use?
The tester uses JavaScript's built-in RegExp engine, which follows the ECMAScript regex standard.
What flags are supported?
g (global), i (case-insensitive), m (multiline), and s (dotAll) flags are supported.
Can I test regex with special characters?
Yes. Special regex characters like ., *, +, ?, ^, $, {}, [], |, () must be escaped with a backslash if you want to match them literally.
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