Regex tester.
Test JavaScript regular expressions against a sample string. See highlighted matches and capture groups update live as you type.
Tool 11DeveloperLive100% local
§ Pattern workshop
Fast iteration.
Uses the JavaScript regex engine — matches here behave exactly as they will in your browser or Node code.
Why doesn't my regex match across lines?
By default, `.` does not match newlines. Add the `s` flag (dotAll) so the dot covers \n, or use `[\s\S]` as a workaround.
What engine is this?
The JavaScript RegExp engine built into your browser — so it matches how regex behaves in Node, Chrome, Firefox, and Safari. Some constructs from PCRE or Python (look-behinds, possessive quantifiers) behave slightly differently.
Can I save a pattern?
Not yet — the tool is intentionally stateless. Copy the pattern and keep it in your own snippets file.