~/tools$ ./use
Regex Tester
About this tool
Test your regular expressions against sample text right in the browser. See every match with its start and end position, inspect the capture groups, and view the matched spans highlighted in the original text. No sign-up.
Frequently asked questions
Which regex engine is used?
Go's RE2 engine, the same safe linear-time engine used by Go's regexp package. It does not backtrack, so patterns can never blow up in time; features like lookahead and backreferences are not supported.
What do the flags do?
case-insensitive applies (?i), multiline makes ^ and $ match at every line boundary by applying (?m), and dot-all makes . match newlines by applying (?s).