PropChain — NFT Property Marketplace

A decentralized marketplace for virtual property NFTs with escrow-based trading and passive yield earnings, built on Ethereum.

Live Demo: propchain-marketplace.vercel.app

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Features

• Property NFTs (ERC-721) — Mint virtual properties with on-chain metadata (name, location, area)
• Marketplace with Escrow — List properties for sale, buy directly, or make escrow-backed offers
• Custom Currency (PROP) — All transactions use the PROP ERC-20 token
• Passive Yield — Property owners earn PROP tokens over time, claimable per-property or in batch
• 5% Marketplace Fee — Configurable fee on every sale, collected to a designated address
• Full Security — ReentrancyGuard, Ownable access control, SafeERC20 transfers

Deployed Contracts (Sepolia)

Contract	Address
PropToken (ERC-20)	0x5fb379720B34f3d2d5C54Ac6644C84972Ef702ca
PropertyNFT (ERC-721)	0xdfFC2E373c6E5d51783f62F0b1124EEa052a276A
PropertyMarketplace	0x7EA151ec169123b8c8804696bc218697009a92b1
PropertyYield	0x6e0A0Da2C0f29e503981da5C960BFEc8c95697c8

Architecture

                    ┌─────────────────┐
                    │   PropToken     │  ERC-20 "PROP" (10M supply)
                    │   (Currency)    │  Ownership → PropertyYield (mints rewards)
                    └────────┬────────┘
                             │
         ┌───────────────────┼───────────────────┐
         │                   │                   │
         ▼                   ▼                   ▼
┌─────────────────┐ ┌─────────────────┐ ┌─────────────────┐
│  PropertyNFT    │ │  Marketplace    │ │  PropertyYield  │
│  (ERC-721)      │ │  (Trading)      │ │  (Rewards)      │
│                 │ │                 │ │                 │
│  • mintProperty │ │  • listProperty │ │  • registerProp │
│  • on-chain URI │ │  • buyProperty  │ │  • pendingYield │
│  • Enumerable   │ │  • makeOffer    │ │  • claimYield   │
│                 │ │  • acceptOffer  │ │  • batchClaim   │
│                 │ │  • cancelOffer  │ │  • yieldRate    │
└─────────────────┘ │  • delistProp   │ └─────────────────┘
                    │  • 5% fee       │
                    └─────────────────┘

Smart Contracts

Contract	Description
PropToken.sol	ERC-20 "PROP" currency token (10M initial supply)
PropertyNFT.sol	ERC-721 property NFTs with on-chain metadata
PropertyMarketplace.sol	Listing, buying, escrow offers with fee system
PropertyYield.sol	Passive PROP earnings for property holders

Tech Stack

• Contracts: Solidity 0.8.24, Hardhat, OpenZeppelin v5
• Frontend: Next.js 14, React 18, TypeScript, Tailwind CSS
• Web3: Wagmi v2, Viem v2, RainbowKit v2, TanStack React Query

Getting Started

Prerequisites

• Node.js 18+
• MetaMask or any WalletConnect-compatible wallet

Contracts

cd contracts
npm install
npm run compile
npm run test            # 48 tests
npm run node            # start local node
npm run deploy:local    # deploy to localhost

Frontend

cd frontend
npm install
cp .env.local.example .env.local
# Fill in contract addresses from deploy output
npm run dev

Deploy to Sepolia

cd contracts
cp .env.example .env
# Fill in SEPOLIA_RPC_URL, PRIVATE_KEY, ETHERSCAN_API_KEY
npm run deploy:sepolia

Seed Demo Data

After deploying, populate the marketplace with demo properties:

# Set contract addresses (from deploy output) in your .env or export them
npm run seed:sepolia

This mints 6 properties, registers them for yield, and lists 4 on the marketplace.

User Flow

1. Admin mints property NFTs (name, location, area)
2. Owner lists a property on the marketplace with a PROP price
3. Buyer either buys directly or makes an escrow offer
4. Seller accepts offer — NFT transfers atomically, PROP distributed (minus 5% fee)
5. Owner earns passive PROP yield over time from held properties
6. Owner claims accumulated yield anytime

Test Coverage

PropChain
  PropToken (2 tests)
  PropertyNFT — Minting (6 tests)
  Marketplace — Listings (6 tests)
  Marketplace — Direct Buy (3 tests)
  Marketplace — Escrow Offers (7 tests)
  Marketplace — Fees & Admin (5 tests)
  Security — Reentrancy (2 tests)
  PropertyYield (9 tests)
  Access Control (5 tests)
  Integration — Full Flow (2 tests)

48 passing

Screenshots

Marketplace	My Properties
Browse & buy listed properties	Manage portfolio, list/delist, claim yield

License

MIT