PlotProof

DEMO VIDEO: https://youtu.be/h3dMZPKe5tg ANDROID APK: https://github.com/chris-netizen/plotproof/releases/latest (enable "install from unknown sources", fund the in-app wallet at faucet.monad.xyz, then stake / check / sell) PlotProof is a public, on-chain registry that helps people avoid land fraud — where the same plot is sold to multiple buyers and "papers" can't be verified. WHAT I BUILT A two-sided product on Monad. Owners and surveyors use a Flutter mobile app to stake a claim while standing on the plot — capturing a photo, GPS, timestamp, and optional title/survey documents. Only a hash of that evidence goes on-chain, so documents stay private but become tamper-evident and permanent. When a plot is sold, the owner transfers the claim to the buyer's wallet (fingerprint-gated), creating a verifiable chain of custody. Anyone can verify any plot on the public dashboard — two different claimants on the same spot are flagged as a possible double sale. THE PROBLEM Land fraud costs Nigeria an estimated $4B/year. Under 10% of land is formally registered, so double-sales thrive and buyers find out too late. PlotProof is a public, tamper-proof place to check who claimed a plot, when, and with what evidence — before you pay. A citizen-first evidence-and-conflict layer that works today, without waiting for government. WHAT I LEARNED - An honest trust model: it anchors evidence and flags conflicts, but doesn't "prove" ownership (documents can be forged) — verification/attestation is the roadmap. - Real web3 infra limits: Monad's public RPC caps eth_getLogs to 100 blocks / 25 req/sec, so I built the indexer around small windows, concurrency, time budgets, and direct state reads (getClaimsBatch) for instant checks. - Shipping solo end-to-end: Solidity + Foundry, Flutter (burner wallet, biometrics, geohash hashing), Next.js on Vercel. Check before you pay.