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Regex Cheatsheet

Regex

Complete regex reference with live pattern tester

Where the standalone Regex Tester is built for iterating on a specific pattern against your own text, this is the lookup-first companion: reference tables for the syntax you've forgotten (a lookahead, a named group, a character class), a live tester panel to try an example against sample text, and a keyword search so typing "email" or "whitespace" surfaces a relevant pattern instead of writing one from scratch. It's based on JavaScript's native RegExp (ECMAScript) syntax, close to PCRE but diverging in places like Unicode property escapes and possessive quantifiers. The example patterns are solid starting points but not necessarily production-ready. Things like email and URL validation carry a lot of edge cases, so critical validation logic should get cross-checked against your language's standard library or a well-tested package rather than trusted as-is. Everything here runs client-side.

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How to use Regex Cheatsheet

  • 1.Browse the reference tables to look up the exact syntax for a lookahead, named group, or character class you've forgotten.
  • 2.Use the live tester panel to try a pattern from the cheatsheet against your own sample text before pasting it into your code.
  • 3.Search the cheatsheet by keyword (e.g. "email" or "whitespace") to quickly find a relevant example pattern instead of writing one from scratch.

Frequently asked questions

What regex flavor does the reference cover?
It's based on JavaScript's native RegExp (ECMAScript) syntax, which is close to PCRE but differs in some areas like Unicode property escapes and possessive quantifiers.
Is my test input sent anywhere?
No, the live tester runs entirely in your browser using JavaScript's RegExp engine.
Are the example patterns production-ready (e.g. for email validation)?
They're good starting points for common cases, but things like email and URL validation have many edge cases — for critical validation, cross-check against your language's standard library or a well-tested package.
Where do I build and test a full pattern?
Use the dedicated Regex Tester tool for a larger, side-by-side pattern/text testing workspace with match highlighting.

Use via API, SDK, or MCP

cURLcurl "https://api.utilix.tech/v1/tools/regex-cheatsheet" \
  -H "Authorization: Bearer utx_live_..."
# Free: 1,000 req/day · Pro: 10,000 req/day

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