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Free Online Regex Tester & Debugger

Test regular expressions in real-time. See matches and capture groups instantly.

Regular Expression
Presets:
//g

Checking in a background worker...

Test String
Enter text to test against the regex
Matches
0 matches
Matches will be highlighted here...

How the Regex Tester Works

Our regex tester uses JavaScript's built-in regular expression engine to validate and test your patterns in real-time. As you type, matches are instantly highlighted and capture groups are displayed.

Features

Test patterns with global, case-insensitive, multiline, and dotAll flags. See individual matches with their positions and capture groups. Use preset patterns for common validations like email, URL, and phone numbers.

Privacy First

All testing happens locally in your browser. Your regex patterns and test data never leave your device.

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What this tool does

Find JavaScript regular-expression matches in sample text.

How to use it

Enter a pattern without slash delimiters, select flags, and add test text. Inspect matches and groups.

Worked example

Pattern a+ with flag g against baaac returns aaa at index 1.

Limitations and checks

This uses JavaScript regex syntax, not PCRE or .NET. Expensive patterns are time-limited; test representative failing inputs as well as matches.

How your data is processed

The operation runs in your browser. Copy and download actions use your device. Where Save work is offered, a local copy is stored; eligible work can sync only under your enabled account settings. See Privacy for site analytics and storage details.

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