External networking

Unity Engine
1

Two questions:

  1. What can I use instead of the deprecated UNet
  2. How can I bind an in game chat and an external app to show and send message to both in game chat and the external app?
2
  1. UNet isn’t deprecated completely, you may still use LLAPI and switch to the new platform later on. As of thirdparty solutions, there are plenty options, one popular is Photon Networking.
  2. This depends on the external app. If it has an api for embedding in applications, what you want will be achieved natively. In chat programs there is some server dispatching messages between clients. It will consume messages from your app and feed them to clients.
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  1. https://discussions.unity.com/t/727663
  2. If you develop the chat solution in house, you’d design the external app to talk to the same chat server you set up as used in the game. If you’re using a 3rd party chat service, you’d likely just connect both the game and the app to the same service as if they were the same project. See the 3rd party chat service’s documentation.

The entire Unet is deprecated, including the LLAPI, and has been for nearly a year. Though deprecated doesn’t mean removed. Last post from the devs I saw on its removal was to expect it in 2019.2 or 2019.3, depending on the progress of the new networking solution.

Edit: Looks like they have updated the status of the LLAPI from deprecated to now obsolete, which makes for a pain to even use the documentation. You have to go back to older Unity version documentation just to see what the NetworkTransport class contains.
https://docs.unity3d.com/2019.1/Documentation/ScriptReference/Networking.NetworkTransport.html