Client-side
Regex Tester
Test regular expressions against real sample text with a live match list, capture group extraction, and replacement preview, all running via WebAssembly.
What it does
- Lists every match with start/end position offsets
- Capture group extraction per match
- Regex replacement preview with copy output
- Flags g, i, m, s, u selectable independently
- Sensitive payloads stay in the tab
0 matches
Regular expressions are evaluated by a finite automaton that processes the input string character by character, which means patterns with unconstrained quantifiers on large inputs can hit exponential backtracking — test your pattern here against real sample text with live match highlighting, capture group extraction, and replacement preview, all running via WebAssembly so sensitive payloads stay in the tab.