What regex flavor does this use?

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.

What do the flags mean?

g (global) finds all matches. i makes matching case-insensitive. m makes ^ and $ match line boundaries. s makes . match newlines (dot-all mode).

How do I capture groups?

Wrap parts of your pattern in parentheses, e.g. (\\w+)@(\\w+). Captured groups are shown in the Match Details section.

Is there a match limit?

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 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.

Regex Tester — Test Regular Expressions Online Free

Test and debug regular expressions with live match highlighting and group capture. Free online regex tester.

Regular Expression

//g

Flags:

Test String

Highlighted Matches0 matches

The quick brown fox jumps over the lazy dog. Pack my box with five dozen liquor jugs.

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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

Use Cases

Test regex online guide Best Dev Tools 2026 Greedy vs Lazy Regex Email Regex Validation

Why Use Irreva for Regex Tester?

Debug complex regular expressions quickly

Test patterns before using them in code

Learn regex by seeing matches in real time

Runs 100% in your browser — files never leave your device.

No account, no sign-up, no subscription — free forever.

Works on any device: desktop, tablet, or mobile.

Frequently Asked Questions

Regex101 alternative

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