Writing to Network

In the previous section, you learned how to read data from the Solana network. Now explore how to write data to it. Writing to the Solana network involves sending transactions that contain one or more instructions.

Programs (smart contracts) process these instructions according to their business logic for each respective instruction. When you submit a transaction, the Solana runtime executes each instruction in sequence and atomically (meaning either all instructions succeed or the entire transaction fails).

In this section, you'll see two basic examples:

Transferring SOL between accounts
Creating a new token

These examples show how to build and send transactions to invoke Solana programs. For more details, refer to the Transactions and Instructions and Fees on Solana pages.

Transfer SOL

Start with a simple example of transferring SOL between accounts. To transfer SOL from the Playground wallet, you need to invoke the System Program's transfer instruction.

A key concept of Solana's account model requires that only the program that owns an account can deduct an account's lamport (SOL) balance. This means if you want to transfer SOL from a wallet account, you must invoke the System Program since it appears as the program owner in the owner field of the account.

Open Example

Click this link to open the example in Solana Playground. You'll see the following code:

client.ts

import {
  LAMPORTS_PER_SOL,
  SystemProgram,
  Transaction,
  sendAndConfirmTransaction,
  Keypair,
} from "@solana/web3.js";

const sender = pg.wallet.keypair;

const receiver = new Keypair();

const transferInstruction = SystemProgram.transfer({
  fromPubkey: sender.publicKey,
  toPubkey: receiver.publicKey,
  lamports: 0.01 * LAMPORTS_PER_SOL,
});

const transaction = new Transaction().add(transferInstruction);

const transactionSignature = await sendAndConfirmTransaction(
  pg.connection,
  transaction,
  [sender],
);

console.log(
  "Transaction Signature:",
  `https://solana.fm/tx/${transactionSignature}?cluster=devnet-solana`,
);

Run Example

Run the code using the run command.

Terminal

$ run

Ensure your Playground wallet has devnet SOL. Get devnet SOL from the Solana Faucet.

Click on the output link to view the transaction details on the SolanaFM explorer.

Transfer SOL

Congratulations. You've just sent your first transaction on Solana.

First, you created an instruction specifying what to do
Then, you added that instruction to a transaction
Finally, you sent the transaction for the Solana network to process

This represents the basic pattern for building transactions to interact with the programs on the Solana.

Create a Token

Next, create a new token using the Token Extensions Program. This requires invoking two instructions:

Create a new account using the System Program
Initialize the account's data as a Mint using the Token Extensions Program

Open Example

Click this link to open the example in Solana Playground. You'll see the following code:

client.ts

import {
  Connection,
  Keypair,
  SystemProgram,
  Transaction,
  clusterApiUrl,
  sendAndConfirmTransaction,
} from "@solana/web3.js";
import {
  MINT_SIZE,
  TOKEN_2022_PROGRAM_ID,
  createInitializeMint2Instruction,
  getMinimumBalanceForRentExemptMint,
} from "@solana/spl-token";

const wallet = pg.wallet;
const connection = new Connection(clusterApiUrl("devnet"), "confirmed");

// Generate keypair to use as address of mint account
const mint = new Keypair();

// Calculate lamports for space required by mint account
const rentLamports = await getMinimumBalanceForRentExemptMint(connection);

// Instruction to create new account with space for new mint account
const createAccountInstruction = SystemProgram.createAccount({
  fromPubkey: wallet.publicKey,
  newAccountPubkey: mint.publicKey,
  space: MINT_SIZE,
  lamports: rentLamports,
  programId: TOKEN_2022_PROGRAM_ID,
});

// Instruction to initialize mint account
const initializeMintInstruction = createInitializeMint2Instruction(
  mint.publicKey,
  2, // decimals
  wallet.publicKey, // mint authority
  wallet.publicKey, // freeze authority
  TOKEN_2022_PROGRAM_ID,
);

// Build transaction with instructions to create new account and initialize mint account
const transaction = new Transaction().add(
  createAccountInstruction,
  initializeMintInstruction,
);

const transactionSignature = await sendAndConfirmTransaction(
  connection,
  transaction,
  [
    wallet.keypair, // payer
    mint, // mint address keypair
  ],
);

console.log(
  "\nTransaction Signature:",
  `https://solana.fm/tx/${transactionSignature}?cluster=devnet-solana`,
);

console.log(
  "\nMint Account:",
  `https://solana.fm/address/${mint.publicKey}?cluster=devnet-solana`,
);

Run Example

Run the code using the run command.

Terminal

$ run

Ensure your Playground wallet has devnet SOL. Get devnet SOL from the Solana Faucet.

You'll see two links printed to the Playground terminal:

One for the transaction details
One for the newly created mint account

Click the links to inspect the transaction details and the newly created mint account on SolanaFM.

Create Token

Mint Account

In this example, you saw how to combine instructions into a single transaction. The transaction contains two key instructions:

Creating a new account using the System Program
Initializing that account as a token mint using the Token Extensions Program

This pattern of combining instructions from different programs into one transaction occurs frequently when building complex Solana transactions. It allows sequential and atomic execution of instructions, ensuring they either all succeed or all fail together.

Writing to Network

Transfer SOL

Open Example

Explanation

Run Example

Create a Token

Open Example

Explanation

Run Example

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