Farm → Processing → Distribution → Retail → Consumer
  │         │            │           │         │
  └── Each step recorded on immutable ledger ──┘
  
Before blockchain: 7 days to trace food origin
After blockchain:  2.2 seconds

solidity
// Simplified smart contract for trade finance
contract TradeFinance {
    struct Letter {
        address buyer;
        address seller;
        uint256 amount;
        bool goodsDelivered;
        bool paymentReleased;
    }
    
    function confirmDelivery(uint256 letterId) external {
        letters[letterId].goodsDelivered = true;
        if (letters[letterId].goodsDelivered) {
            releasePayment(letterId);
        }
    }
}

typescript
// Using Ethers.js for enterprise integration
import { ethers } from "ethers";

class SupplyChainTracker {
  async recordShipment(productId: string, location: string, timestamp: number) {
    const tx = await this.contract.recordEvent(
      ethers.encodeBytes32String(productId),
      location,
      timestamp
    );
    await tx.wait();
    return tx.hash;
  }
  
  async getProductHistory(productId: string) {
    const events = await this.contract.queryFilter(
      this.contract.filters.ShipmentRecorded(productId)
    );
    return events.map(e => ({
      location: e.args.location,
      timestamp: e.args.timestamp,
      blockNumber: e.blockNumber
    }));
  }
}