I could only find one mention and that says: ”The Control API on the LAN is not available for wide release.”. So I reckon there is no public documentation.

https://docs.sonos.com/docs/connected-home-architecture#tag/playback/operation/Playback-LoadContent-GroupId

Thanks, I am a registered Sonos developer, and I still can’t see anything about the LAN api. Nice find on that page BTW.

I can’t find anything either, like literally nothing. I’m not even sure what the LAN API does, I’m wondering if it’s maybe for smart home stuff.

From that I can see the LAN API is pretty much the same as the cloud API, except:

• You make calls to a local device instead of the actual cloud
• To use it, you need a client certificate
• The cloud API itself is maybe 30% documented at this point
• This is what the mobile apps have used since the infamous v80 release and the Desktop app uses it a little bit for some operations

Per the original post about the update, it would appear there is a way to get approved, which I assume comes with a client cert you can use to authenticate.