Which flags are supported?

The tester supports g (global), i (case-insensitive), m (multiline), and s (dotAll) flags.

What happens if my pattern is invalid?

An error message is shown below the pattern input and no highlighting is applied.

Can I copy a pattern from the cheat sheet?

Yes — every row in the reference has a 'Copy' button that copies the example pattern to your clipboard.

Does this send my text to a server?

No — all matching runs entirely in your browser using the built-in JavaScript RegExp engine.

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Regex Cheat Sheet & Tester

Interactive regular expression reference with live pattern testing and match highlighting.

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About this tool

Browse a comprehensive, categorized regex reference covering anchors, character classes, quantifiers, groups, and special characters — each entry includes the symbol, name, description, and a worked example. Use the quick tester at the top to enter any text and pattern and see matches highlighted in real time. One-click copy puts any pattern straight onto your clipboard.

How to use

1 Type or paste your test string into the text area at the top.
2 Enter a regex pattern and choose flags (g, i, m, s) as needed.
3 Matches are highlighted live; the match count is shown below the input.
4 Browse the reference table below and click 'Copy' on any entry to copy that pattern.

Frequently Asked Questions

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