Sony recently launched an Audio Control API. The API enables developers to control certain functionality of compatible Sony devices through smart home automation apps. At launch, developers can control power, volume, and other audio features for three Sony products (i.e. a streaming soundbar, wireless speaker, and an AV receiver).
While Sony has pitched the API as its "first ever Audio Control API," this isn't Sony's first foray into embedding web servers into their physical devices. In fact, certain Sony cameras run web servers that provide third party apps access to the cameras via the Sony Camera Remote API.
The Audio Control API is a derivative of the open source, Scalar API. The API uses standard HTTP and JSON protocols. It uses SSDP for device discovery, and advanced connectivity through DLNA and UPnP. Features accessible through the API include power, volume, sound mode, functions, and multi-zone. Check out the developer site for more information.
Additionally, Sony has published some tutorials for using the API. The API reference provides more granular detail. Before getting started, ensure that the Sony device is properly configured to a network, and it must be accessible from your product.