Token Transfers in Ethereum Development with Go

Understanding ERC-20 Token Transfers

This section guides you through transferring ERC-20 tokens programmatically using Go. For non-ERC-20 tokens, refer to the Smart Contracts chapter for custom contract interaction methods.

Prerequisites

• Established client connection
• Loaded private key
• Configured gas price
• Basic understanding of ETH transfers

Key Implementation Steps

1. Initialize Transaction Parameters

value := big.NewInt(0) // Set ETH value to 0 for token transfers
toAddress := common.HexToAddress("0x4592d8f8d7b001e72cb26a73e4fa1806a51ac79d")
tokenAddress := common.HexToAddress("0x28b149020d2152179873ec60bed6bf7cd705775d")

2. Construct Call Data

Generate the method ID by hashing the function signature:

transferFnSignature := []byte("transfer(address,uint256)")
hash := sha3.NewKeccak256()
hash.Write(transferFnSignature)
methodID := hash.Sum(nil)[:4]

Format recipient address and token amount:

paddedAddress := common.LeftPadBytes(toAddress.Bytes(), 32)
amount := new(big.Int).SetString("1000000000000000000000", 10) // 1000 tokens
paddedAmount := common.LeftPadBytes(amount.Bytes(), 32)

Combine data payload:

var data []byte
data = append(data, methodID...)
data = append(data, paddedAddress...)
data = append(data, paddedAmount...)

3. Estimate and Set Gas Limit

gasLimit, err := client.EstimateGas(context.Background(), ethereum.CallMsg{
    To:   &toAddress,
    Data: data,
})

4. Create and Sign Transaction

tx := types.NewTransaction(nonce, tokenAddress, value, gasLimit, gasPrice, data)
signedTx, err := types.SignTx(tx, types.NewEIP155Signer(chainID), privateKey)

5. Broadcast Transaction

err = client.SendTransaction(context.Background(), signedTx)
fmt.Printf("tx sent: %s", signedTx.Hash().Hex())

👉 Track your transaction on Etherscan

Complete Code Implementation

package main

import (
    // Required imports
    "github.com/ethereum/go-ethereum/crypto/sha3"
    // ... other imports
)

func main() {
    // Full implementation code
    // ... [previous code sections]
}

Best Practices for Token Transfers

1. Always verify contract addresses
2. Use proper error handling
3. Monitor gas prices dynamically
4. Test on testnets before mainnet deployment

FAQ

Why set ETH value to 0 in token transfers?

Token transfers occur within the contract's internal state, not through ETH value transfers. The zero ETH value indicates we're interacting with the contract rather than sending currency.

How can I verify successful token transfers?

👉 Use blockchain explorers to confirm transactions. Look for the transaction hash in the token contract's events log.

What's the purpose of method ID in call data?

The method ID (first 4 bytes of the function signature hash) tells the contract which function to execute, while the subsequent bytes contain the function parameters.

How do I handle different token decimal places?

Always convert token amounts to their base unit (wei equivalent) using the token's decimals value before constructing the transfer call.

For advanced ERC-20 interactions, explore the ERC20 Smart Contract chapter to learn about allowance patterns, event parsing, and batch operations.