AppHelp
Test regular expressions instantly
Build a pattern and see live matches, capture groups, and replacements — everything runs locally.
Matches: 2
a@example.com [8, 21)
Group 1: a
Group 2: example
Named groups
word: a
b@apphelp.net [25, 38)
Group 1: b
Group 2: apphelp
Named groups
word: b
Features
- Live match list with index ranges
- Numbered and named capture groups
- Replace preview with $1 and $<name> support
- Runs entirely in the browser
Frequently asked questions
- Which regex flavor does this use?
- It uses the JavaScript RegExp engine, supporting the g, i, m, s, u, y, and d flags.
- Does replace support capture references?
- Yes. The replacement field supports $1 style numbered groups and $<name> named groups.
- Does it upload my pattern or text?
- No. Matching and replacing happen entirely in your browser.