What these cards are

Every card on Tradeo is a real, physically graded trading card — PSA, SGC or CGC slabbed — sitting in a professional vault. Courtyard.io tokenised it, which means there is an NFT on the Polygon blockchain representing that exact slab.

You are not buying a picture. You are buying the card. If you ever want the physical object, it can be redeemed and shipped to you.

Buying

Tradeo does not sell you the card and does not take a cut. Hitting Buy sends you to that card's listing on OpenSea, where the sale happens as a normal on-chain order.

That is deliberate. OpenSea already handles escrow, payment and transfer safely, and re-implementing it here would add risk without adding anything useful.

How ownership works

Once you have bought a card, the NFT is in your wallet. There is no registration step and nothing to claim.

Your collection page asks Polygon what your wallet holds, every time you open it. Tradeo stores no record of ownership, which means nothing here can go stale and nothing here can say you own a card the blockchain disagrees about.

Trading

This is the part OpenSea cannot do: swapping a card directly for another card, with no money involved.

You pick one of yours and one of theirs and sign an offer. Signing is free and moves nothing. When the other person accepts, both cards move in a single transaction — or the transaction fails and neither moves. There is no moment where one person has both cards.

Settlement runs through Seaport, the same audited contract OpenSea itself uses. Tradeo only carries the signed offer between you: it cannot settle a trade itself, and it cannot alter one without invalidating your signature.

Why two wallets

Sign-in uses Phantom. That is only your identity — a signature proving the wallet is yours, which costs nothing and is not a transaction.

The cards themselves live on Polygon, so holding and trading them needs an EVM wallet like MetaMask. That is why the collection page asks separately.

What to watch out for

Prices shown are live asks pulled from OpenSea. Some sellers list at absurd prices they never expect to hit, so a card marked at seven figures is not a valuation.

Trades are final. Once a swap settles on-chain there is no undo, no support ticket and no reversal — that is what makes it trustless in the first place.