BulkTransfer - Airdrop Tool

A Solidity smart contract for efficient bulk token and ETH transfers, perfect for airdrops, batch payments, and mass distributions.

Features

• Bulk ERC20 Token Transfers: Send tokens to multiple addresses in a single transaction
• Bulk ETH Transfers: Distribute ETH to multiple recipients efficiently
• Static Value Distribution: Send the same amount to all recipients
• Dynamic Value Distribution: Send different amounts to each recipient
• Gas Optimization: Reduce transaction costs by batching transfers
• Owner Controls: Contract owner can withdraw accumulated ETH and transfer ownership

Contract Functions

Static Value Transfers

Send the same amount to all recipients:

// ERC20 tokens
transferStaticValue(address _tokenAddress, address[] memory _to, uint256 _value)

// ETH
transferStaticValue(address[] memory _to, uint256 _value) payable

Dynamic Value Transfers

Send different amounts to each recipient:

// ERC20 tokens
transferDynamicValues(address _tokenAddress, address[] memory _to, uint256[] memory _values)

// ETH
transferDynamicValues(address[] memory _to, uint256[] memory _values) payable

Usage Examples

ERC20 Token Airdrop (Static Amount)

const recipients = [
  "0x742d35Cc6634C0532925a3b8D4C9db96590c6C87",
  "0x8ba1f109551bD432803012645Hac136c22C177ec",
  "0x1234567890123456789012345678901234567890"
];

const tokenAddress = "0xYourTokenAddress";
const amountPerRecipient = ethers.utils.parseUnits("100", 18); // 100 tokens

await bulkTransfer.transferStaticValue(tokenAddress, recipients, amountPerRecipient);

ETH Airdrop (Dynamic Amounts)

const recipients = [
  "0x742d35Cc6634C0532925a3b8D4C9db96590c6C87",
  "0x8ba1f109551bD432803012645Hac136c22C177ec"
];

const amounts = [
  ethers.utils.parseEther("0.1"), // 0.1 ETH
  ethers.utils.parseEther("0.2")  // 0.2 ETH
];

const totalValue = ethers.utils.parseEther("0.3");

await bulkTransfer.transferDynamicValues(recipients, amounts, { value: totalValue });

Prerequisites

• For ERC20 transfers: Approve the BulkTransfer contract to spend your tokens first
• For ETH transfers: Send sufficient ETH with the transaction to cover all transfers

Security Features

• Input validation for all parameters
• Balance checks before transfers
• Protection against zero addresses
• Owner-only functions for contract management
• Event emission for transfer tracking

Gas Optimization

This contract significantly reduces gas costs compared to individual transfers:

• Single transaction for multiple recipients
• Optimized loops and storage usage
• Minimal external calls

Events

event TokensTransferred(address indexed from, address[] indexed to, uint256 value);

Tracks all bulk transfers with sender, recipients, and total value.

Owner Functions

• transferOwnership(address newOwner): Transfer contract ownership
• withdraw(): Withdraw accumulated ETH from the contract

Installation & Deployment

1. Install dependencies:

npm install @openzeppelin/contracts

2. Compile the contract:

npx hardhat compile

3. Deploy to your preferred network:

npx hardhat run scripts/deploy.js --network [network-name]

License

MIT License - see LICENSE file for details.

Security Considerations

• Always test on testnets before mainnet deployment
• Verify recipient addresses before bulk transfers
• Consider gas limits for large recipient lists
• Ensure sufficient token allowances for ERC20 transfers

Contributing

Contributions are welcome! Please ensure all changes include appropriate tests and follow Solidity best practices.