Steam App ID and Multiplayer Matchmaking.

As far as I’m aware, you need to have a custom App ID (NOT ID=480) in order for online subsystem “find sessions” to work across the internet and not just LAN. Is that so? If yes, can I obtain a custom Steam App ID without needing to “publish” my game to steam before hand?


Not sure about appid 480 and online.
After getting the AppId from steam, you are far from going public still, but you can use everything already.