tools / text & data
regex tester
Live match highlighting, capture groups, and a common-pattern library.
//
flags
matches
enter a pattern and some text
result
common patterns
note: JavaScript's regex engine backtracks. A pathological pattern (e.g. (a+)+$) on a long non-matching string can stall this tab — the match/length caps limit matchcount, not time inside a single attempt. There's no perfect ReDoS guard; everything runs locally, so only your own tab is ever at risk.
examples