Mastering Blockchain Programming with Solidity

Data

Data represents the hexadecimal data that you want to transfer along with a transaction. This data field is required to call a method of a contract.

When transferring ETH from one EOA to another EOA, the data field is empty, which means the value of the data field will be 0x. However, when we want to execute a method of a contract, the data field will hold the hexadecimal value of the method and its arguments:

Transaction data in hexadecimal from etherscan.io

The preceding hexadecimal transaction data, once decoded, represents the transfer() method call (called on an ERC20 contract) with the _to and _value parameters passed in. As you ...