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Regex Tester

Test regular expressions with live highlighting. View capture groups, match positions, and replace results. 30+ common patterns ready to use.

/ /
Flags:
g global
i ignore case
m multiline
s dotAll
u unicode

Match Details

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Common Patterns Library

Regular Expression Quick Reference

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Regex (regular expressions) are patterns used to match character combinations in strings. The most important metacharacters: . matches any character, * matches zero or more, + matches one or more, ? makes the previous optional, ^ anchors to start, $ anchors to end, \d matches digits, \w matches word characters, \s matches whitespace, and [abc] matches a, b, or c.

Use the Regex Tester above — enter your values and get instant results. This free online tool calculates regex tester online free javascript without any download or signup required. Results update in real time as you type.
Use the Regex Tester above — enter your values and get instant results. This free online tool calculates how to test regex without any download or signup required. Results update in real time as you type.
A capture group is a portion of a regex enclosed in parentheses () that captures the matched text for later use. Captured groups are numbered starting at 1. In a replacement string, $1 refers to the first group, $2 to the second, and so on. Non-capturing groups use (?:...) and match without capturing. Named groups use (?<name>...) and can be referenced as $<name> in replacements.