Build a transaction

First we need to make a transaction message.

import { createTransactionMessage } from "@solana/transaction-messages";

let message = createTransactionMessage({ version: 0 });

The idea of a message vs a transaction can be confusing. In Kit, a TransactionMessage does not actually become a Transaction until its compiled.

Then usually we want to add a fee payer

import { address } from "@solana/addresses";
import { setTransactionMessageFeePayer } from "@solana/transaction-messages";

const myAddress = address("mpngsFd4tmbUfzDYJayjKZwZcaR7aWb2793J6grLsGu");
message = setTransactionMessageFeePayer(myAddress, message);

For the transaction to land on-chain we need to provide a recent blockhash

import { setTransactionMessageLifetimeUsingBlockhash } from "@solana/transaction-messages";

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

Then we can add our instructions:

import { appendTransactionMessageInstruction } from "@solana/transaction-messages";

const memoTransaction = appendTransactionMessageInstruction(
    {
        data: new TextEncoder().encode("Hello world!"),
        programAddress: address("MemoSq4gqABAXKb96qnH8TysNcWxMyWCqXgDLGmfcHr"),
    },
    message,
);

So we have a bunch of instruction adding methods:

• appendTransactionMessageInstruction
• appendTransactionMessageInstructions
• prependTransactionMessageInstruction
• prependTransactionMessageInstructions

Usually we are not doing this one step at a time, instead we build up transactions through a series of functions we pipe through:

import { pipe } from "@solana/functional";
import {
    appendTransactionMessageInstruction,
    createTransactionMessage,
    setTransactionMessageFeePayer,
    setTransactionMessageLifetimeUsingBlockhash,
} from "@solana/transaction-messages";

const transferTransactionMessage = pipe(
    createTransactionMessage({ version: 0 }),
    m => setTransactionMessageFeePayer(myAddress, m),
    m => setTransactionMessageLifetimeUsingBlockhash(latestBlockhash, m),
    m => appendTransactionMessageInstruction(getTransferSolInstruction({ source, destination, amount }), m),
);