Regex Tester

A fast, client-side regex tester with live match highlighting and capture group extraction. Type a pattern and flags, paste your test string, and see matches light up instantly with amber highlights. Supports all JavaScript regex flags (global, case-insensitive, multiline, dotAll, unicode).

The match details panel shows every match with start/end indices, numbered capture groups, and named groups. Safe handling of zero-length matches prevents infinite loops. Everything runs in your browser — nothing is sent to a server.