What regex flavor does this use?

This tool uses JavaScript's built-in RegExp engine, which supports most common regex features including character classes, quantifiers, lookahead, lookbehind, groups, and backreferences.

What are the available flags?

You can toggle four flags: g (global — find all matches), i (case-insensitive), m (multiline — ^ and $ match line boundaries), and s (dotAll — . matches newlines).

Why does my pattern show an error?

If the regex pattern is syntactically invalid (e.g. unmatched parentheses or brackets), the tool will display the error message from the JavaScript engine. Fix the syntax and the error will clear automatically.

Regex Tester

Write and test regex patterns with real-time match highlighting. Supports flags and capture groups. View match count, captured groups, and match indices. Invalid patterns are caught and reported immediately. Everything runs in your browser — your text never leaves your device.

Regex Pattern

Flags:gims

Your files are processed entirely in your browser. Nothing is uploaded to any server.

How to Use Regex Tester

1
Paste or type your text
Enter your text in the input area. You can paste from clipboard or type directly.
2
See instant results
The tool processes your text automatically as you type. Adjust options if available.
3
Copy the output
Click the copy button to save the result to your clipboard. No data leaves your browser.

Frequently Asked Questions

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