is it possible to add a message on a ETH transfer

Yes, it is possible to add a message on an Ethereum (ETH) transfer. This can be done by using the "data" field when sending a transaction. This field allows you to include additional information or a message along with the transfer. However, not all wallets or platforms may support this feature, so be sure to check beforehand.

Metamask does not currently support adding messages to Ethereum transactions through their user interface. However, you can manually add a message to an Ethereum transaction using the ethers.js library.

You can use the data field in the overrides object when sending a transaction using ethers.js to include a message. Here is an example of how you can do this:

const { ethers } = require("ethers");

const provider = new ethers.providers.Web3Provider(web3.currentProvider);
const signer = provider.getSigner();

const message = "Hello from ethers.js!";
const tx = {
  to: recipientAddress,
  value: ethers.utils.parseEther("0.1"),
  data: ethers.utils.formatBytes32String(message),
};

const sendTx = async () => {
  const txResponse = await signer.sendTransaction(tx);
  await txResponse.wait();
  console.log("Transaction sent successfully!");
};

sendTx();

In this example, the data field is used to include the message "Hello from ethers.js!" in the transaction. Remember that the data field must be formatted properly, such as with formatBytes32String, to ensure it is encoded correctly.

Make sure to test your code on a test network first before sending any transactions on the mainnet.

To decode a message from an Ethereum transaction, you can use the ethers.js library. Here is an example of how you can decode the message from a transaction:

const { ethers } = require("ethers");

const provider = new ethers.providers.JsonRpcProvider("https://mainnet.infura.io/v3/your_infura_project_id");

const txHash = "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef";
provider.getTransaction(txHash).then((tx) => {
  const message = ethers.utils.parseBytes32String(tx.data);
  console.log("Decoded message:", message);
});

In this example, we are using the provider.getTransaction(txHash) method to fetch the transaction details using the transaction hash. We then use ethers.utils.parseBytes32String(tx.data) to decode the message from the data field of the transaction. The decoded message is then printed to the console.

Make sure to replace the txHash with the actual transaction hash that you want to decode. Also, ensure that you have a valid Infura project ID or use a different provider URL if needed.

You can run this code in a Node.js environment or in a browser with appropriate configurations.

Etherscan provides an API that allows you to retrieve transaction details, including the data field, which can be used to extract any messages or additional information included in the transaction. Here is an example of how you can retrieve transaction details and decode a message using the Etherscan API:

const axios = require("axios");

const apiKey = "Your_Etherscan_API_Key";
const txHash = "0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef";

const apiUrl = `https://api.etherscan.io/api?module=proxy&action=eth_getTransactionByHash&txhash=${txHash}&apikey=${apiKey}`;

axios.get(apiUrl)
  .then(response => {
    const data = response.data.result;
    const message = web3.utils.hexToAscii(data.input);
    console.log("Decoded message:", message);
  })
  .catch(error => {
    console.error("Error retrieving transaction details:", error);
  });

In this example, we use the Etherscan API to retrieve transaction details for a specific transaction hash. We then extract the input field from the response data, which contains the data field of the transaction. We use web3.utils.hexToAscii to decode the message from the hexadecimal format.

Remember to replace Your_Etherscan_API_Key with your actual Etherscan API key and txHash with the transaction hash you want to decode.

Other blockchain explorers or services may also provide similar APIs for retrieving transaction details, so you can explore their documentation to find the relevant endpoints and parameters for decoding messages from transactions.