nng

nng, short for nanomsg-next-gen, is an open-source high-performance messaging library designed for asynchronous interprocess and network communication. It serves as the successor to nanomsg, offering a cohesive API and a modular transport layer to support scalable messaging in distributed systems.

It provides a C library with a socket-like API. Applications create sockets, configure a protocol (such as request/reply, publish/subscribe, pair, survey/respond, or bus), and send and receive messages over connected endpoints. The core model uses pipes and endpoints to manage connections, enabling asynchronous I/O and non-blocking operation. A single application can mix protocols and transports to suit different components.

Transports include in-process, inter-process, and network options (for example, TCP). The library is designed to be portable across major platforms and aims for a small, deterministic footprint. Security features are available through optional transports and configurations, enabling encrypted or authenticated communication where supported by the build.

nng is open source and community-maintained, with bindings and wrappers available for various languages beyond C. It is widely used in research and production environments that require lightweight, reliable messaging without external dependencies. The project emphasizes simplicity of use, robust error handling, and clean API design as its guiding goals.