Rexact

ONLINE

The regex test bench.

What Rexact does

Tests each regex against the cases you provide.
Detects patterns that can block the engine (ReDoS).
Checks portability across 7 engines: JavaScript, PCRE, Python, RE2, Java, .NET and grep.
Provides a pattern cheatsheet (email, IBAN, French postal code, French VAT, etc.).

Privacy. Your regexes are not sent to any Rexact server. No account, no key.

Rexact is a NM Labs product. It also exists as an MCP server: Rexact MCP.