Xbox One: Buy games without Xbox Gold?

I would like to buy Star Wars The Old Republic 1 & 2 on Xbox One soon, to buy the game do I need Xbox Gold? And of course to play it?

You do not need gold. You only need this if you want to play online and use the Partychat.

Everything else, chat, marketplace and friends list, and send messages works with the normal XBox live (formerly Silver) account at no extra cost.

However, you need an Xbox live account and an internet connection. Where the former costs you nothing.

Need you do it only the free silver membership