Deck building and format checks exist for Magic: The Gathering, Riftbound, and the One Piece Card Game. Other catalogue games can still be collected and traded.

Build a deck

1. 1Go to Your Decks and click Add Deck. The modal title is Create a deck
2. 2Enter a Name (3–30 characters) and pick the Game
3. 3If that game has formats, pick Format. Some games skip this field
4. 4Optionally paste a Deck list. Expand Deck list format help for that game’s syntax. Check Use cheapest printings? if the importer offers it
5. 5Click Create. You land on the new deck at /x/decks/<game>/<id>. New decks start private

On the deck

• Add or remove cards, then check format legality — illegal cards are marked
• Collection gap shows which copies you still need from your collection
• Your Decks can filter by Format (All, or a format you play) and sort the list

Visibility is Private or Public. There is no Unlisted option. Publish from the deck after you create it — the create modal does not set visibility.

• Private — only you
• Public — listed on /decks and shareable