Card Tracker
The Bloomberg terminal for baseball cards. Real MLB data. USDC escrow on Arc. Buy the dip
Project Description
Card Tracker is a baseball card trading marketplace powered by real MLB performance data. Our AI engine pulls live stats from MLB.com and ESPN to generate buy/sell/hold signals for PSA 10 graded cards. Price history shows 1-week, 3-month, and 1-year eBay sale trends with liquidity scores showing how many days it takes to sell each card. The marketplace uses USDC on Arc (Circle's L1 blockchain) for payments, with a Solidity escrow smart contract (CardEscrow.sol) that holds funds until the seller confirms shipment and the buyer confirms receipt — fully trustless with automatic refunds if the seller doesn't ship within 7 days. Wallet onboarding is powered by Dynamic SDK. ENS name resolution shows .eth names in the trader leaderboard. Built with Next.js, wagmi, viem, and Hardhat.
How it's Made
Built with Next.js 15 and TypeScript. Real-time MLB player stats are pulled directly from the MLB Stats API (no API key required) and ESPN's public API for live news that affects card values. Our signal engine combines batting average, home runs, OPS, last game performance, and 14-day eBay price momentum to generate confidence-scored BUY/SELL/HOLD signals for PSA 10 graded cards. The core innovation is CardEscrow.sol — a Solidity 0.8.20 smart contract deployed on Arc testnet (Circle's purpose-built stablecoin L1, chainId 5042002). It implements a multi-step conditional escrow: buyer deposits USDC → FUNDED → seller confirms shipment with tracking → SHIPPED → buyer confirms receipt → COMPLETE, with automatic 2.5% platform fee split on settlement. If the seller never ships, the buyer claims a full refund after 7 days. Disputes go to platform arbitration. This makes peer-to-peer card trading fully trustless for the first time. Dynamic SDK handles wallet onboarding — buyers connect any EVM wallet in seconds. ENS resolution via viem's getEnsName shows .eth names in the trader leaderboard instead of raw addresses. Wagmi v2 manages onchain state. CoinGecko provides live crypto prices. The trader leaderboard tracks unrealized gains across positions with analyst ratings and price targets per card.
