What regex flavor does this use?

This uses JavaScript regular expressions (ECMAScript flavor), which is the same as what runs in browsers and Node.js.

Can I use flags like global and case-insensitive?

Yes. You can add flags (g, i, m, s, u) to your pattern. The global flag (g) is enabled by default to show all matches.

What are capture groups?

Capture groups (defined with parentheses) extract specific parts of a match. For example, (\d{4})-(\d{2}) captures year and month separately from a date string.

Regex Tester

Pattern Tools

Enter a regex pattern and test string to see matches highlighted in real time. View capture groups, match indices, and named groups. Includes a library of common patterns (email, URL, IP, phone, date).

100% client-side processing

Regex Pattern

Flags

Test String

How to Use Regex Tester Online

Paste your data into the input field above
The result appears instantly in the output area
Click "Copy" to copy the result to your clipboard

Test regular expressions with live highlighting and capture groups. Runs 100% client-side — no data is sent to any server.

Frequently Asked Questions

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