Ethereum: How to findout the sender of a transaction

Deciphering Ethereum Transactions: A Guide to Finding Input Addresses

Ethereum’s blockchain provides a wealth of information about transactions, allowing developers to analyze and understand the inner workings of the network. One aspect of this analysis is finding input addresses, which are essential for identifying who paid for certain transactions or services. In this article, we’ll explore how to find out which addresses were used as inputs in a given transaction using your own software.

What are Input Addresses?

Input addresses in Ethereum transactions represent the parties that provided value or resources (known as tokens) for the service being executed on the network. These input addresses can be used to identify who paid for a transaction or service, enabling developers to understand the economic context of the activity.

How ​​to Find Input Addresses

There are several ways to find input addresses in Ethereum transactions using your own software:

• Ethereum’s JSON-LD Output Format

  : One approach is to use Ethereum’s JSON-LD output format, which provides a structured representation of transaction data. By parsing this JSON-LD output, you can extract the input addresses and other relevant information.

• Ethers.js: Ethers.js is a popular JavaScript library for working with Ethereum transactions. It includes a built-in function to retrieve input addresses from a transaction’s JSON-LD output.

• Ethers.js API: The Ethers.js API provides an interface for interacting with the Ethereum blockchain, including retrieving transaction data and input addresses.

Using Ethers.js or Ethers.js API

Here’s an example of how you can use Ethers.js to find input addresses in a given transaction:

const ethers = require('ethers');


const transaction = await ethers.getContractOnBlockNumber(

  '0x6d0e6c8a6ce2ebf9a4df5b1ab43dc3d2a42ca76cc', // transaction ID

  [new ethers.Address('0x...')], // input addresses (optional)

  { blockNumber: 10000 } // optional block number to filter by

);


if (transaction) {

  console.log(Input addresses for transaction ${transaction.hash}:);

  const inputs = transaction.inputs;

  if (inputs.length > 0) {

    console.log(inputs.map((input) => input.address));

  }

} else {

  console.log('Transaction not found');

}

Tips and Considerations

When working with Ethereum transactions, keep in mind the following:

• Transaction metadata: Transaction data includes information such as sender addresses, transaction hashes, block numbers, and gas limits. You can use this metadata to infer input addresses.

• Input address formatting: Input addresses are represented using hexadecimal strings, which can be extracted from JSON-LD output or parsed directly.

• Optimization: Finding input addresses may require some processing power and computational resources.

By understanding how to retrieve input addresses in Ethereum transactions, you’ll gain valuable insights into the economic context of specific activities on the network. This knowledge will enable developers to build more efficient, scalable, and transparent systems that leverage the strengths of the Ethereum blockchain.