Developer

Regex Tester

Test regular expressions with live match highlighting.

Pattern//

Highlighted matches
Quick reference

This free regex tester lets you build, debug, and understand regular expressions with instant feedback across multiple flavors — JavaScript, PCRE2 (PHP), Python, Golang, Java, .NET, and Rust. Pick a flavor to adapt the available flags and named-group syntax; non-JS flavors are approximated with warnings when a target engine lacks a feature (for example, RE2 has no lookaround or backreferences). Type a pattern and toggle flags, paste your test string, and every match is highlighted live. The match details panel breaks down each match with its position, numbered groups, and named capture groups. The substitution tab shows a live replace result with full support for $1, $<name>,$&, $`, and $' tokens. The explanation tab decodes your pattern token by token, and a built-in quick reference covers the common syntax.

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