We’re happy to let you know the multiplayer mode for No Man’s Sky on GOG.COM has entered beta. It’s available now via GOG Galaxy on the „Experimental Multiplayer" beta branch and will be rolling out to everyone soon.

If you’d like to start playing NMS multiplayer in beta right now, first you need to be signed up to beta branches in GOG Galaxy. To do that, once you have the game installed on your machine, and added to Galaxy, select it from the side-bar on the left. Then click on MORE -> Settings, and look for the BETA CHANNELS setting in the top-right corner. To enable beta branches change this setting to ON.
Now, choose the „Experimental Multiplayer” branch from the UPDATES: CHANNEL drop-down list.

Let us know how you like it and enjoy the game!

There is no GOG and Steam crossplay, unfortunately.

There are no plans to add crossplay at the moment.

This is entirely the developer's decision, so I cannot say if that's possible or not. We will definitely make a big buzz around it if it happens.