Regex Tester
Write a pattern, paste sample text, and see matches and capture groups highlighted live.
How to read the results
The highlighted preview shows every match in place; the match list below spells out each match's text, position and capture groups (the parts of your pattern wrapped in parentheses). Switching flags changes everything live: g finds all matches instead of one, i ignores letter case, m makes ^ and $ match line starts and ends.
Frequently asked questions
Which regex flavor is this?
JavaScript (ECMAScript). Most patterns are portable to PCRE/Python, but lookbehind and unicode handling differ slightly across languages.
Can a bad pattern freeze the page?
A pathological pattern with catastrophic backtracking can hang this tool — it runs in your browser, so only your tab is affected. Reload to recover.