Regex Explainer

Understand regex without guessing

Regular expressions pack a lot of meaning into a short pattern. This explainer parses JavaScript regex syntax and describes each token in plain language, from character classes and quantifiers to anchors and groups. Paste sample text to see whether the pattern matches in real time.

Pair with testing and reference tools

After you understand a pattern, validate matches with the Regex Tester or look up syntax in Regex Memo. All parsing runs locally in your browser.

Frequently Asked Questions

Which regex flavor is supported?

JavaScript regular expressions, including the global, ignore case, multiline, dotAll, and Unicode flags. Lookaheads, lookbehinds, named groups, and lazy quantifiers are described in plain language.

Can it explain lookaheads?

Yes. Positive and negative lookaheads and lookbehinds are broken out as their own steps, including the pattern inside them.

Is my pattern sent to a server?

No. Explanation and match tests run entirely in your browser.

Do I need slashes around the pattern?

You can paste either a raw pattern or a literal form such as /pattern/flags. Inline flags are respected when present.

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Understand regex without guessing

Pair with testing and reference tools

Frequently Asked Questions

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