How does the generator work?

It detects common prefixes/suffixes, digit sequences, letter sequences, and fixed characters across your examples to build a pattern using constructs like \d+, [a-zA-Z]+, and alternation.

Will the generated regex always be perfect?

It provides a best-effort pattern. For complex cases you may need to refine it manually, but it gives you a solid starting point.

Can I test additional strings after generating?

Yes — type any string into the test field to see whether the generated pattern matches it in real time.

What regex flavor is used?

The generated pattern follows JavaScript RegExp syntax, which is also compatible with most modern languages.

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Regex Pattern Generator

Generate regex patterns automatically from positive and negative example strings.

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About this tool

Provide positive examples (strings that should match) and negative examples (strings that should NOT match), and the tool will infer and generate a suitable regular expression. It detects common prefixes, suffixes, digit sequences, and letter sequences to build patterns using \d+, [a-zA-Z]+, \w+, and alternation. Test the generated pattern against your examples instantly and copy it for use in code.

How to use

1 Step 1: Enter one or more positive examples — strings the pattern must match.
2 Step 2: Optionally add negative examples — strings the pattern must NOT match.
3 Step 3: Click Generate to receive a suggested regex pattern.
4 Step 4: Review the match results and copy the regex to your clipboard.

About this tool

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