This information will be on the Campaign page or in the search area.
When browsing Campaigns in the search, you will see a platform icon under the name of the game as shown below:
The first Campaign on the list has Nintendo keys of specific regions, that you can see if you hover over the icon. The other two Campaigns are available on Steam (PC).
On the Campaign page, you can see the platforms and types of keys available.
Here, we can see they are Nintendo keys. Hovering will display all the specific region types, as well as display if a specific region is out of keys, as we can see by the greyed-out last N icon.
If you are invited to a Campaign, in the Invite tab, you will see the icon next to the name of the Campaign, similar to how it is when you are browsing Campaigns.
If you see a Campaign that is out of keys, or you have received a duplicated code, please reach out to our support team so we can assist you!