Question 1

Which flavor of regex does this generate?

Accepted Answer

By default the output is PCRE-compatible and runs as-is in JavaScript (ECMAScript), Python, Go, Java, and most other modern regex engines. Some flavor-specific tokens — like lookbehind in older JS engines — will be flagged in the explanation.

Question 2

How do I use the generated regex in JavaScript?

Accepted Answer

Wrap the pattern in slashes with the flags after — for example /pattern/gi — or pass it as a string to new RegExp(pattern, 'gi'). Use String.prototype.match, matchAll, replace, or test depending on what you need.

Question 3

What do the flags mean?

Accepted Answer

g matches all occurrences (not just the first), i is case-insensitive, m makes ^ and $ match line boundaries instead of the whole string, and s lets . match newlines. The tool picks sensible defaults but you can edit them.

Question 4

Why does the explanation not match the regex exactly?

Accepted Answer

The token breakdown explains each meaningful piece — character classes, quantifiers, groups — in order. If the regex contains literal punctuation, it shows up as 'literal x' rather than as a separate token. If you spot a real mismatch, regenerate or refine the description.

Question 5

Can I use this for password validation?

Accepted Answer

You can, but consider whether you actually need a regex. Most password rules — minimum length, character class requirements — are clearer when written as a sequence of small checks. Regex is a great fit for extraction and matching, less so for boolean validation against many rules.

Question 6

Does the test panel save my pasted text?

Accepted Answer

No. The test panel runs entirely in your browser. Pasted text never leaves your device.

Regex Generator

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When to use it

Real input, real output

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