I would have code here but I honestly have no idea how I'd even start this stuff. I checked ROBLOX's WebAPI and still found nothing, if you have any way to help me out, please do so!
COMMUNITY QUESTION
How to detect if your friend is online in-game?
1 answer
i don't really got what you asked but i think this might help.
game.Players.PlayerAdded:connect(function()
print("There are Player in the game!")
end)
This discussion is preserved as it was. New answers, comments, and votes are closed.

2 comments
http://wiki.roblox.com/index.php?title=API:Class/TeleportService/GetPlayerPlaceInstanceAsync - Only if they are in the same universe though
If you have a Valkyrie account, you can use https://valkyrie.crescentcode.net/api/friends/getFriends