Everything you need to know about the game mechanics, payouts, and architecture.
SpaceX Cards is an on-chain card pulling game on Solana. Players pay 0.1 SOL per pull and receive a random rocket card. Each card has a fixed payout that is returned to the player's wallet.
| Tier | Rockets | Chance | Payout | House edge |
|---|---|---|---|---|
| Common | Electron, Soyuz | 60% | 0.02 SOL | +0.08 SOL |
| Rare | Falcon 9, Atlas V | 25% | 0.05 SOL | +0.05 SOL |
| Epic | Falcon Heavy, Delta IV Heavy | 10% | 0.08 SOL | +0.02 SOL |
| Legendary | SLS, Saturn V | 4% | 0.15–0.2 SOL | -0.05 to -0.1 SOL |
| Mythic | Starship | 1% | 0.5 SOL | -0.4 SOL |
The expected payout per pull is calculated as:
On average, the house retains 0.056 SOL per pull. This margin funds operations and the payout pool.
Transaction sent to the house wallet. Confirmed on-chain.
API checks the transaction exists, amount is correct, and sender matches.
HMAC-SHA256(server_secret, tx_signature) produces the random seed. Impossible to predict or manipulate.
The house wallet sends the payout amount back to the player automatically.
Card selection uses HMAC-SHA256(SERVER_SECRET, transaction_signature). The server secret is never exposed to clients. Each transaction signature is unique, so results can't be replayed or predicted. In production, this will be replaced with Switchboard VRF for fully on-chain provable randomness.