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Regex Explainer

Get plain English explanations of regex patterns

Regex Explainer is a free online tool from BrowserUtils that get plain english explanations of regex patterns. It runs entirely in your browser — your data never leaves your device. No account required.

How to use Regex Explainer

  1. 1 Paste or type your input into the editor above.
  2. 2 The tool processes your data instantly — right in your browser, with nothing sent to a server.
  3. 3 Copy the result with one click or continue editing your input.

About Regex Explainer

Free online regex explainer. Paste a regular expression and get a detailed, token-by-token breakdown in plain English. This tool runs entirely in your browser — your data is never sent to a server. Just paste your input, get instant results, and copy with one click. No sign-up or installation required.

Regex Explainer specs

Runtime
100% client-side (browser)
Built on
Native JavaScript String, Intl.Segmenter, and RegExp APIs with full Unicode support
Cost
Free — no account, no rate limits, no usage caps
Browser support
Chrome 90+, Firefox 88+, Safari 14+, Edge 90+
Part of
299 developer tools on BrowserUtils (100% client-side)

Questions

What regex tokens are explained?
The explainer covers literals, metacharacters (. ^ $ * + ? |), character classes ([abc], \d, \w, \s), quantifiers ({n,m}), groups (capturing, non-capturing, lookaheads), anchors, and backreferences.
Can I test my regex too?
For testing regex with match highlighting, use the companion Regex Tester tool. This tool focuses on explaining what each part of the pattern does.
Is the regex explainer useful for understanding someone else's code?
Yes, paste a regex you found in existing code and the explainer will break it down token by token in plain English so you can understand exactly what it matches.
Does the regex explainer handle lookaheads and lookbehinds?
Yes, lookahead (?=...) and lookbehind (?<=...) assertions are explained with descriptions of what they assert without consuming characters in the match.
Does the regex explainer work offline?
Yes, the pattern parsing and explanation generation run entirely in your browser. No internet connection is required after the page has loaded.
Embed this tool

Copy this code to embed the tool on your website. Adjust the height to fit your layout.

<iframe src="https://www.browserutils.dev/embed/regex-explainer" width="100%" height="500" frameborder="0" title="Regex Explainer"></iframe>

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