> RegexTester.dev
Free regex tester: real engines, debugger & benchmarks
[ about ]
RegexTester.dev is a free online regex tester and validator that lets users test, validate and match regular expressions instantly, with real-time highlighting.
It supports multiple regex flavors, including JavaScript, PCRE2, Python, Java, .NET 10, Go, PCRE, Rust and Formal (CS Theory), selectable from a flavor menu. Features include match results, test-string annotation, replace, sample and unit-test tabs, a quick-reference panel, save/share, and a pattern gallery.
The site also lists a regex debugger, a benchmark suite and a cross-engine compatibility checker. It states "No signup · No cookies · Runs in your browser."