Is my text private?
Yes. The editor, the regex engine and your saved patterns all live in your browser. Nothing you type is sent to a server.
Which regex flavors are supported?
Patterns run on your browser's own JavaScript engine, which handles named groups, look-behind and Unicode property escapes. For PCRE, Python, .NET, Java, Ruby and Go, common syntax like (?P<name>…) groups, \A and \z anchors and POSIX classes is translated for you. Anything that can't be translated is flagged.
How does the hover linking work?
Each match in your text is tied to a card in the results panel. Hover a match and its card is highlighted; hover a card and the text scrolls to its match. It helps a lot when a pattern has many matches.
Can I see capture groups?
Yes. Each match lists its numbered and named groups with exact start and end positions, and groups are underlined in the text. Groups that didn't take part in a match are shown too.
Can I test replacements?
Yes. Switch to Replace and use $1, $2, $<name>, $& and similar references. The result updates as you type, with the replaced parts highlighted.
Are my patterns saved?
Your current workspace is remembered between visits, and you can save named patterns to a local library. They stay on your device; share a link to move a pattern somewhere else.
Does it work offline?
Yes. Once the page has loaded, matching, replacing and your saved patterns all work without a connection.
