Node.js Node-API is a C++ module that provides header-only wrapper classes to simplify the use of Node-API, a C-based API provided by Node.js for building native addons. It offers a C++ object model and exception handling semantics with low overhead, allowing developers to write native Node.js addons using C++. The module supports different Node-API versions and is designed to work with the active LTS Node.js versions, with the oldest supported version being Node.js 18.x.