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Regex Generator

Regex Generator gives you correct, ready-to-use regular expressions for the patterns developers need most — emails, URLs, IP addresses, hex colors, slugs, UUIDs, dates and more. Pick a preset and copy the expression, no syntax wrangling required.

Each pattern comes with a plain-English explanation and a live tester so you can confirm it matches your own values before pasting it into code. A token cheat sheet covers the building blocks if you want to tweak a pattern by hand.

Pick a pattern

Matches a typical email address: local part, an @, a domain and a top-level domain.

✓ Matches the pattern

Token cheat sheet

\dAny digit (0–9)
\wWord char: letter, digit or _
\sWhitespace (space, tab, newline)
^Start of string / line
$End of string / line
+One or more of the previous
*Zero or more of the previous
?Zero or one (optional)
{n,m}Between n and m repetitions
[...]Any one character in the set
(...)Capturing group
|Alternation: this OR that

How to use Regex Generator

  1. 1

    Pick a pattern

    Choose from presets like Email, URL, IPv4, Hex color, Slug, UUID, Date and Strong password.

  2. 2

    Copy the regex

    The generated expression appears ready to copy, alongside a one-line explanation of what it matches.

  3. 3

    Test and tweak

    Type a sample value to see an instant ✓ or ✗, then adjust the pattern using the token cheat sheet if you need a variation.

Why start from a preset?

Many everyday patterns — validating an email, checking an IPv4 octet is within 0–255, matching a canonical UUID — are surprisingly easy to get subtly wrong. A pattern that looks right can accept malformed input or reject valid input, and those bugs are hard to spot by reading the regex alone.

Starting from a tested preset removes that risk. Each expression here is anchored with ^ and $ where appropriate so it matches the whole value rather than just a fragment, and the live tester lets you sanity-check it against real data before you trust it in production.

Reading and adapting the patterns

The token cheat sheet covers the core building blocks: character classes like \d, \w and \s; anchors ^ and $; quantifiers +, *, ? and {n,m}; sets in square brackets; groups in parentheses; and alternation with the pipe. With these you can read any of the presets and adapt them — for example loosening a username length or adding a country to a phone format.

When you change a pattern, re-run the tester with both values that should match and values that shouldn't. Confirming the negative cases is just as important as the positive ones, because an over-permissive pattern is a common source of validation bugs.

Frequently asked questions

Are these regular expressions production-ready?
They are correct, anchored patterns suitable for typical validation. As with any regex, test them against your own data — especially edge cases — before relying on them.
Will these work outside JavaScript?
The patterns use standard regex syntax that works in most languages. A few constructs differ between engines, so verify in your target language if you use it elsewhere.
Does this use AI to generate patterns?
No. It offers a curated set of hand-verified presets and a cheat sheet — predictable and offline, with no model guessing.
Can I test my own value?
Yes. Type any value into the tester and you'll get an instant match or no-match result against the current pattern.

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