Step 1 - Getting game URL from Stadia

First, open Stadia and launch the game you wish to add to GOG.

Then, when the page has opened, press and hold Esc to exit full screen.

Finally, copy the game’s url from the top of the web browser.

Step 2 - Bridging the gap

Create a folder on your PC to keep all your Stadia game links.  I keep mine in the folder where I install my games from Steam and GOG etc.  We will be making two files: a link, and a batch file that opens the link.  This means that the games will open in your default browser, and if the game’s URL changes for any reason, we only have to edit a link, not the batch file, though that isn’t hard to do.  If you are confident with batch files, feel free to make one that opens the URL directly instead.

First, create a new shortcut

Then, enter the url we copied from Stadia

When asked, you should name the shortcut with the game’s title.

Then create a new text file, don’t bother naming it; or just open notepad.

Enter the following, make sure to change ‘Celeste’ to the name of your link.

Go to File > Save As, select the folder you keep your link in, and name it the same as your link, with a .bat at the end.  This should create a batch file.

Once you can see the batch file you can delete the text file (if you have one).

Now if you run the bat file, it should open your default browser with the game running in Stadia.

Step 3 - Adding game to GOG

On GOG Galaxy’s Recent tab, select ‘Add games & friends’, and select add game manually.

Search for the game you wish to add, and click marked as owned.

Open the game’s page in your library, and select ‘link executable’.

Select your .bat file.

Now, when you click the play button, your game should launch in your browser.