How to Add a Memo to a Transaction

import {
  getExplorerLink,
  createTransaction,
  createSolanaClient,
  getSignatureFromTransaction,
  signTransactionMessageWithSigners,
} from "gill";
import { loadKeypairSignerFromFile } from "gill/node";
import { getAddMemoInstruction } from "gill/programs";

const { rpc, sendAndConfirmTransaction } = createSolanaClient({
  urlOrMoniker: "devnet", // or `mainnet`, `localnet`, etc
});

const { value: latestBlockhash } = await rpc.getLatestBlockhash().send();

// load a Signer from the default Solana CLI keypair file
const signer = await loadKeypairSignerFromFile();

const transaction = createTransaction({
  version: "legacy",
  feePayer: signer,
  instructions: [
    getAddMemoInstruction({
      memo: "Memo message to send in this transaction",
    }),
  ],
  latestBlockhash,
});

const signedTransaction = await signTransactionMessageWithSigners(transaction);

console.log(
  "Sending transaction:",
  getExplorerLink({
    cluster: "devnet",
    transaction: getSignatureFromTransaction(signedTransaction),
  }),
);

await sendAndConfirmTransaction(signedTransaction);