# API Reference

This chapter documents the functions and data structures that make up
the _NNG_ programming interface.

> [!NOTE]
> Interfaces not documented here are not considered public or stable,
> and they may be removed or altered in incompatible ways at any time.

We have organized the reference material along general functional areas.
They are:

- Messages
- Sockets
- Contexts
- Options
- Dialers, Listeners, and Pipes
- [Asynchronous I/O](aio/index.md)
- [Asynchronous I/O for Providers](aio_provider/index.md)
- [Utility Functions](util/index.md)
- Threads and Synchronization
- HTTP Client
- HTTP Server
- TLS Support
- Connected Streams
- Statistics
- Legacy Compatibility