A regex workbench with flag toggles, matches tinted in place under the caret, a capture-group table, verbatim engine errors, and a worker-backed time budget that survives catastrophic backtracking.
npx shadcn@latest add @zyeon/regex-testerZyeon UI limits how often it can be asked, and Regex Tester hasn't had its turn. Its source will show here once it has.