NAPI

N-API, also known as Node-API, is a stable C API for building native addons for Node.js. Its goal is to provide an ABI-stable interface that allows addons to be compiled once and run across multiple Node.js versions without recompilation. By abstracting away engine-specific details, N-API aims to reduce the churn caused by changes to the underlying JavaScript engine.

The API defines a set of types and functions that enable native code to create and manipulate JavaScript values, objects, and functions, invoke JavaScript from native code, and handle errors. Core concepts include an environment handle (env), opaque JavaScript value handles (napi_value), and result codes (napi_status). It also supports module registration, property access, function creation, and lifecycle management, as well as asynchronous work and thread-safe calls. The standard interface is designed to be language-agnostic, with C as the primary implementation language, while bindings for C++ are commonly provided via higher-level wrappers.

N-API was developed by the Node.js community to provide binary compatibility across Node.js releases independent of the JavaScript engine behind Node (such as V8). Addons compiled against a given N-API version typically remain usable on newer Node.js versions as long as that N-API version remains supported. Node-Addon-API is a popular C++ wrapper that simplifies working with N-API. Build tooling such as node-gyp and cmake-js support compiling against N-API. The ecosystem uses .node addon binaries loaded via require, enabling native performance and functionality within Node.js applications.