How to use the Regex Tester

Enter your regular expression pattern in the Pattern field.
Enable flags as needed: g finds all matches, i ignores case, m makes ^ and $ match line boundaries.
Paste your test string — matches are highlighted in real time and capture groups are shown below.

JavaScript regex syntax quick reference

. matches any character. \d matches a digit, \w a word character, \s whitespace. Use + for one or more, * for zero or more, ? for optional. Wrap groups in (…), alternation in a|b, character classes in […]. Use \b for word boundaries.