Regex from Text Generator

About this tool

Regex Generator from Text Samples turns one or more sample strings into an escaped regular-expression pattern. Simple mode joins the samples as alternatives. Smart mode extracts a common prefix and suffix and groups the differing middle text. A single sample therefore produces an exact escaped match, while multiple samples produce a pattern that matches those supplied alternatives or their shared prefix/suffix structure. The tool explains the generated pattern visually through the result and includes a test field so you can try additional strings. Treat the output as a starting point: it does not infer semantic formats such as a valid email, date, or IP address from examples, and you should test edge cases in the Regex Tester before using it in code.

Why use it

• Escapes special characters like . ( ) and ? for you.

• Smart mode factors shared prefixes and suffixes out of a word list.

• Built-in test field shows matches as you type.

• Saves time when you need a pattern that matches a known list of strings.

• Gives a starting point to refine in the Regex Tester.

• Runs entirely in your browser.

How to use

1. Enter one or more sample strings you want the regex to match (one per line).
2. Choose Smart (extract prefix/suffix) or Simple (join with |).
3. Click Generate Regex; the pattern appears as /pattern/g.
4. Type in the Test input field to see which parts of a string match.
5. Click Copy pattern to copy the /pattern/g literal.
6. For a single sample, use Simple mode — Smart mode is meant for two or more different samples.

When it helps

• Matching a fixed list of keywords, product codes or file names.
• Turning a list of words into one compact alternation pattern.
• Quickly creating a starting pattern to refine in a regex tester.
• Escaping a literal string that contains regex metacharacters.
• Seeing how a common prefix or suffix can be pulled out of alternatives.

Examples

Tips

• Use Simple mode for a single sample; Smart mode needs at least two different samples.
• After generation, paste the regex into the Regex Tester tool to verify it against additional samples.
• The pattern only matches the strings you listed — add more samples to cover more cases.
• Use anchors (^ and $) when validating whole strings so partial matches are rejected.
• Remove the surrounding slashes and g flag when pasting into Python, PHP or Java code.

Frequently Asked Questions

Glossary

Regular expression (regex)

A string-based pattern language for matching and extracting text content.

Character class

A set of characters in brackets like [a-z] or [0-9] that match any one character from the set.

Quantifier

A regex symbol like *, +, or ? that specifies how many times the preceding element can occur.

Anchor

A regex element like ^ (start) or $ (end) that asserts position rather than matching characters.

Capture group

Parentheses in a regex that group elements and capture the matched text for later use.

PCRE

Perl Compatible Regular Expressions — a regex syntax variant supported by most modern engines.