Regex Editor & Tester

Matches nested parenthesized strings using PCRE recursion via the (?-2) backreference, allowing it to handle arbitrarily deep balanced parentheses. A lookahead captures the full structure (with outer parens) in group 1 and the inner content in group 2. The (?-2) recursively matches valid nested groups, while [^()]+ handles non-paren content. Used for parsing nested function calls, mathematical expressions, or structured data.