CppInterOp provides compiler-as-a-service capabilities using Clang-REPL, enabling dynamic languages to interoperate with C++. This talk covers its technical architecture, including runtime template instantiation, C++ overload resolution, and JitCall - a lightweight runtime wrapper generator. We demonstrate how CppInterOp's API, built on Clang's AST, enables practical Python-C++ interoperability, including use cases like invoking CUDA kernels from Python and cross-language inheritance between Python and C++ classes.