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Deploying to Multiple Blockchain Networks

This guide explains how to deploy the DTA Provenance smart contracts to various blockchain networks including Polygon and Arbitrum mainnets and testnets.

Overview

The blockchain implementation supports multiple networks:

  • Polygon (Mainnet) - Low-cost, Ethereum-compatible L2
  • Polygon Amoy (Testnet) - Free testnet for Polygon (replaces Mumbai)
  • Arbitrum One (Mainnet) - High-performance Ethereum L2
  • Arbitrum Sepolia (Testnet) - Free testnet for Arbitrum
  • Localhost - Local development with Hardhat Network

Prerequisites

Required

  • Node.js v16+ and npm
  • A crypto wallet (MetaMask recommended)
  • Private key for deployment account

Optional (for verification)

Setup

1. Install Dependencies

cd blockchain
npm install

This will install: - hardhat - Development framework - @nomicfoundation/hardhat-verify - Contract verification plugin - dotenv - Environment variable management - ethers.js - Ethereum library - @openzeppelin/contracts - Secure contract libraries

2. Configure Environment

Copy the example environment file:

cp .env.example .env

Edit .env and add your configuration:

# Your private key (WITHOUT the 0x prefix)
PRIVATE_KEY=your_64_character_private_key_here

# Polygon Configuration
POLYGON_RPC_URL=https://polygon-rpc.com
POLYGON_AMOY_RPC_URL=https://rpc-amoy.polygon.technology
POLYGONSCAN_API_KEY=your_polygonscan_api_key

# Arbitrum Configuration
ARBITRUM_RPC_URL=https://arb1.arbitrum.io/rpc
ARBITRUM_SEPOLIA_RPC_URL=https://sepolia-rollup.arbitrum.io/rpc
ARBISCAN_API_KEY=your_arbiscan_api_key

# Optional: Enable gas reporting
REPORT_GAS=false

Security Warning

  • NEVER commit your .env file to version control
  • NEVER share your private key
  • Use a separate wallet for testing with minimal funds
  • The .env.example file is safe to commit (no secrets)

3. Get Test Tokens

For testnet deployments, you need free test tokens:

Polygon Amoy Testnet

  1. Get MATIC from Polygon Faucet
  2. Select "Polygon Amoy" network
  3. Enter your wallet address
  4. You'll receive ~0.5 test MATIC

Arbitrum Sepolia Testnet

  1. Get Sepolia ETH from Sepolia Faucet
  2. Bridge to Arbitrum Sepolia via Arbitrum Bridge
  3. Or use Chainlink Faucet for Arbitrum Sepolia directly

For better reliability, use dedicated RPC providers:

  1. Sign up at alchemy.com
  2. Create apps for each network you need
  3. Copy the API keys and update .env:
POLYGON_RPC_URL=https://polygon-mainnet.g.alchemy.com/v2/YOUR_KEY
POLYGON_AMOY_RPC_URL=https://polygon-amoy.g.alchemy.com/v2/YOUR_KEY
ARBITRUM_RPC_URL=https://arb-mainnet.g.alchemy.com/v2/YOUR_KEY
ARBITRUM_SEPOLIA_RPC_URL=https://arb-sepolia.g.alchemy.com/v2/YOUR_KEY

Infura (Alternative)

  1. Sign up at infura.io
  2. Create projects for each network
  3. Update .env with Infura URLs

Deploying Contracts

Local Development

Start a local Hardhat node:

npm run node

In another terminal, deploy:

npm run deploy:local

Testnet Deployment

Polygon Amoy

npm run deploy:polygon-amoy

Arbitrum Sepolia

npm run deploy:arbitrum-sepolia

Mainnet Deployment

Mainnet Warning

Mainnet deployments cost real money. Double-check: - Contract code is audited - You have enough tokens for gas - You're deploying to the correct network

Polygon Mainnet

npm run deploy:polygon

Arbitrum One

npm run deploy:arbitrum

Contract Verification

Verification makes your contract source code publicly available on block explorers.

Automatic Verification

Add --verify flag or set VERIFY=true:

# During deployment
npx hardhat run scripts/deploy-with-verify.js --network polygonAmoy --verify

# Or with environment variable
VERIFY=true npm run deploy:polygon-amoy

Manual Verification

If automatic verification fails:

# Get contract address from deployments/{network}.json
npx hardhat verify --network polygonAmoy 0xYourContractAddress

Check Verification Status

Visit the block explorer:

Deployment Tracking

Deployment information is saved in blockchain/deployments/{network}.json:

{
  "address": "0x1234567890abcdef...",
  "network": "polygonAmoy",
  "chainId": 80002,
  "deployer": "0xYourWalletAddress...",
  "timestamp": "2024-02-09T12:34:56.789Z",
  "blockNumber": 12345678,
  "txHash": "0xTransactionHash...",
  "verified": true,
  "verifiedAt": "2024-02-09T12:35:30.123Z"
}

Interacting with Deployed Contracts

Use the interact script with any network:

# Polygon Amoy
npm run interact:polygon-amoy

# Arbitrum Sepolia
npm run interact:arbitrum-sepolia

# Polygon Mainnet
npm run interact:polygon

# Arbitrum One
npm run interact:arbitrum

The script automatically: 1. Reads the deployed contract address from deployments/{network}.json 2. Connects to the existing contract 3. Runs example transactions (register provenance, verify, etc.)

Network Comparison

Network Type Chain ID Avg Gas Price Tx Cost* Block Time Finality
Polygon Mainnet L2 137 ~30 gwei ~$0.01 2s 128 blocks (~4 min)
Polygon Amoy Testnet 80002 Free Free 2s ~30s
Arbitrum One Mainnet L2 42161 ~0.1 gwei ~$0.01 0.25s 1 block
Arbitrum Sepolia Testnet 421614 Free Free 0.25s ~30s
Ethereum Mainnet Mainnet L1 1 ~50 gwei ~$5-50 12s 15 blocks (~3 min)

* Approximate cost for registering a provenance record at current prices

Cost Estimates

Registration Transaction (~100,000 gas)

Network Gas Price ETH Price Cost per Tx Cost per 1000 Tx
Polygon 30 gwei $0.80 MATIC $0.0024 $2.40
Arbitrum 0.1 gwei $2,000 ETH $0.02 $20
Ethereum 50 gwei $2,000 ETH $10 $10,000

Cost Optimization

  • Use L2s: Polygon and Arbitrum are 100-500x cheaper than Ethereum mainnet
  • Batch operations: Register multiple records in one transaction
  • IPFS storage: Store full metadata off-chain, only hash on-chain
  • Monitor gas: Deploy during low-traffic times

Troubleshooting

"Insufficient funds" Error

Make sure your wallet has: - Enough tokens to pay for gas - A small buffer (add 20% extra)

Check balance: 

# Your wallet address is shown at deployment start
# Visit network block explorer and search for your address

"Nonce too high" Error

Your local nonce is out of sync:

# Reset Hardhat's cached nonce
npx hardhat clean
rm -rf cache/ artifacts/

"Invalid API Key" Error

Check your .env file: - API keys are correct - No extra spaces or quotes - File is named .env (not .env.example)

"Network not supported" Error

Ensure: 1. Network is configured in hardhat.config.js 2. You're using the correct network name 3. RPC URL is accessible (test with curl)

RPC Connection Issues

Try these solutions:

  1. Use Alchemy/Infura: Public RPCs can be unreliable
  2. Check rate limits: Free tiers have request limits
  3. Wait and retry: RPC might be temporarily down
  4. Switch RPC: Try alternative public endpoints

Best Practices

Development Workflow

  1. Local First: Test thoroughly on Hardhat Network
  2. Testnet Deploy: Deploy to testnet (Amoy/Sepolia)
  3. Testnet Test: Run full test suite on testnet
  4. Audit: Get professional audit for mainnet
  5. Mainnet Deploy: Deploy to production network

Security Checklist

  • [ ] Private key stored securely (never in code)
  • [ ] Contract code audited by professionals
  • [ ] Tests passing with 100% coverage
  • [ ] Upgradability considered (if needed)
  • [ ] Access controls properly configured
  • [ ] Emergency pause mechanism tested
  • [ ] Deployment wallet has minimal funds

Gas Optimization

// Good: Batch operations
function batchRegister(
    string[] calldata names,
    string[] calldata uris,
    bytes32[] calldata hashes
) external {
    for (uint i = 0; i < names.length; i++) {
        _registerProvenance(names[i], uris[i], hashes[i]);
    }
}

// Avoid: Individual transactions
// Each call costs base tx fee (~21,000 gas)

Monitoring

After deployment, monitor:

  1. Transaction status: Ensure confirmations
  2. Gas usage: Track actual vs estimated costs
  3. Contract events: Set up event listeners
  4. Error rates: Monitor failed transactions

Advanced Topics

Multi-Sig Deployment

For production, use a multi-sig wallet:

  1. Deploy Gnosis Safe on target network
  2. Fund the Safe with deployment funds
  3. Create deployment transaction in Safe
  4. Collect required signatures
  5. Execute deployment

Upgradeable Contracts

Consider OpenZeppelin's upgradeable contracts:

npm install @openzeppelin/contracts-upgradeable

Use UUPS or Transparent Proxy pattern for upgradeability.

Custom Networks

Add new networks in hardhat.config.js:

networks: {
  customNetwork: {
    chainId: 12345,
    url: "https://rpc.custom.network",
    accounts: [process.env.PRIVATE_KEY]
  }
}

Resources

Documentation

Tools

Block Explorers

Faucets

Next Steps

Support