Squared

Squared is an onchain IOU tracker for the small debts that live in group chats and memory — transport money, data top-ups, a lunch someone covered. Log a debt against a friend's wallet on Monad Testnet and it appears on both sides. It settles one of two ways: the debtor pays MON directly through the contract, or the creditor confirms they were paid offline (cash, bank transfer) — the debtor alone can never mark a debt settled, so no one can erase what they owe. Every entry is timestamped and permanent. Built with a Foundry smart contract (11-test suite, verified on MonadVision and Monadscan) and a React + wagmi frontend with a Reown AppKit multi-wallet modal — MetaMask, Coinbase, or any mobile wallet via WalletConnect QR — wrapped in a ledger-book visual identity: ruled paper, margin rule, stamp. What I learned: deploying and verifying contracts on Monad with Foundry, wiring wagmi + AppKit so visitors without a browser extension can still connect from a phone, and designing settlement permissions so the person owed — not the debtor — controls when a debt dies. Monad's fast finality makes the whole loop feel instant.