Quickstart: Set up and transfer USDC on Solana

This step-by-step guide teaches you how to write a script to send 10 USDC between two wallets using the Solana Devnet, which is Solana's testing network.

To better understand the process and its components, you will use third-party tooling such as Javascript libraries, node services, and wallets. Completing this tutorial will help prepare you to integrate USDC payment flows within your app. Building with USDC enables you to move money near-instantly around the globe using decentralized protocols.

USDC is a stablecoin backed 1:1 to the U.S dollar and operates natively on many public blockchains. Like many currencies, USDC is powered by a token contract, a programmable piece of code that manages user balances autonomously across a decentralized network.

As transactions occur, the token contract automatically updates the digital ledger, ensuring real-time tracking of funds. This mechanism allows individuals and businesses to send and receive dollars seamlessly, capitalizing on the transparency, security, and efficiency of blockchain technology.

Before you begin this tutorial, you will need the following apps, tools, and accounts:

1. Circle Mint Sandbox Account: an account that provides access to testnet USDC.

2. Phantom: An app for creating wallets, which are devices for storing USDC on chain:

   1. Create two wallets, one for sending and one for receiving testnet USDC transactions on the Solana Devnet network. These will serve as your origin wallet, from which one you send USDC, and the destination wallet, which receives USDC. Keep note of the addresses for both.

   2. Make sure you securely record the private key for the origin wallet.

   3. Import the Solana Devnet USDC token contract into your origin wallet to enable it to read the token balance. Note the contract address: 4zMMC9srt5Ri5X14GAgXhaHii3GnPAEERYPJgZJDncDU

3. Node.js: JavaScript runtime environment to run code locally on your machine.

4. Web3.js: JavaScript library containing functions to call the USDC token contract and initiate transactions.

5. Code Editor: A source code editor of your choice. One example, Visual Studio, is available as a desktop application.

Follow the steps in this tutorial to transfer USDC on Solana:

1. Navigate to Circle's signup page, enter your information in the required fields, and click "Sign Up." Completing the signup process takes you to the sandbox account Home:

2. Navigate to the APIs tab in the sidebar, and click the “CREATE A KEY” button:

   1. Complete the “Key Name” field.

   2. Click the “CREATE KEY” button. A modal title “API Key Created” will populate upon success.

   3. Click “SHOW” to view the value of your new key.

   4. You must click the key to record a copy of its value.

You will need to use native gas tokens to pay the transaction (gas) fee:

1. Configure the Circle sample sandbox application by adding your API key:

   1. Navigate to sample-sandbox.circle.com.

   2. Click on the settings (gear) menu in the top right-hand corner.

   3. Complete the field for "Your API Key" with the value from your sandbox account.

   4. Click on the hamburger button in the top left corner to access API methods.

2. Mint testnet USDC with a simulated bank transfer using methods in the Core Functionality menu:

   1. Click the POST /businessAccount/banks/wires menu item.

      1. Click the PREFILL FORM button and then choose US BANK ACCOUNT to add a simulated bank account for testing.

      2. Click the MAKE API CALL button.

      3. Copy the value for the id key.

   2. Click the GET /businessAccount/banks/wires/{id}/instructions menu item.

      1. Complete the Account Id field using the value of the id key returned from the previous step.

      2. Click the MAKE API CALL button.

      3. From the successful response, record the value of the trackingRef and accountNumber fields.

   3. Click the POST /mocks/payments/wire menu item.

      1. Complete the Tracking Ref and Account Number fields with the values you recorded from the previous step.

      2. Complete the Amount field with a dollar amount you choose for your mock payment.

      3. Click the MAKE API CALL button.

3. Add the SOL wallet address to your address book:

   1. You can use a REST client to make a POST request to the address recipients endpoint. The sandbox app does not yet support SOL blockchain:

      Shell

      curl -X POST \
        --url https://api-sandbox.circle.com/v1/addressBook/recipients \
        --header 'accept: application/json' \
        --header "Authorization: Bearer <YOUR_SANDBOX_API_KEY>" \
        --header 'content-type: application/json' \
        --data '{"idempotencyKey": "<YOUR_IDEMPOTENCY_KEY>", "address": "<YOUR_ADDRESS>", "chain": "SOL", "metadata": {"email": "", "bns": "", "nickname": "" } }'
      

      CopyCopied!

   2. Record the value of the id from the successful response.

4. Click the POST /payouts menu item.

   1. Complete the Amount field with a dollar amount you choose for your mock payment.

   2. Complete the id field with the values you recorded from the previous step.

   3. Click the MAKE API CALL button.

5. Request testnet SOL:

   1. In a new browser tab or window, navigate to the Solana Faucet.

   2. Complete the Enter Solana account address field with your Fantom deposit address from step 2.

   3. Below the wallet address input field, select the amount of SOL tokens you want.

   4. Select the Devnet environment. Your SOL should automatically be air dropped into your wallet upon success.

6. Make payouts in USDC from the Payouts API menu:

   1. From sample-sandbox.circle.com, click the Payounts APIs menu item.

   2. Click the POST /payouts menu item.

   3. Complete the Amount field.

   4. Set the Currency to USD.

   5. Complete the Destination field with the recipient ID that corresponds to your destination wallet address.

   6. Select address_book from the Destination Type drop-down.

   7. Complete the Beneficiary Email with your recipient email address.

   8. Click the MAKE API CALL button.

   9. Record the value of the id for your payout.

7. Monitor your payouts from the Payouts API menu:

   1. From sample-sandbox.circle.com, click the Payounts APIs menu item.

   2. Click  the GET /payouts/{id} menu item.

   3. Complete the Payout Id field with the value of your payout ID from the previous step.

   4. Click the MAKE API CALL button to check the status of your payout.

Install Web3.js by running the command below at the command line.

// Type this command to install libraries
npm install @solana/web3.js @solana/spl-token bs58

In your text editor, create a new JavaScript file called send10.js. Review the commented code below to understand its structure. Copy and paste it into your new file:

// Write JavaScript Code
const bs58 = require('bs58')
const {
  Connection,
  Keypair,
  PublicKey,
  clusterApiUrl,
} = require('@solana/web3.js')

const {
  getOrCreateAssociatedTokenAccount,
  transfer,
} = require('@solana/spl-token')
// Replace these with your own keys and desired transfer amount
const PRIVATE_KEY = '' // Your private key in Base58 encoding
const RECEIVER_PUBLIC_KEY = '' // Receiver's public key
const TRANSFER_AMOUNT = 10000000 // 10 amount of USDC to transfer (in smallest unit)
// The address of the USDC token on Solana Devnet
const USDC_DEV_PUBLIC_KEY = '4zMMC9srt5Ri5X14GAgXhaHii3GnPAEERYPJgZJDncDU'
// Convert the private key from Base58 to a byte array and create a Keypair
const senderPrivateKeyBytes = bs58.decode(PRIVATE_KEY)
const senderKeypair = Keypair.fromSecretKey(senderPrivateKeyBytes)
// Create a new connection to the Solana Devnet
const connection = new Connection(clusterApiUrl('devnet'), 'confirmed')
;(async () => {
  try {
    // Fetch the sender's USDC token account
    const senderTokenAccount = await getOrCreateAssociatedTokenAccount(
      connection,
      senderKeypair,
      new PublicKey(USDC_DEV_PUBLIC_KEY),
      senderKeypair.publicKey,
    )
    // Fetch or create the receiver's associated token account for USDC
    const receiverTokenAccount = await getOrCreateAssociatedTokenAccount(
      connection,
      senderKeypair,
      new PublicKey(USDC_DEV_PUBLIC_KEY),
      new PublicKey(RECEIVER_PUBLIC_KEY),
      true, // Allow creating a token account for the receiver if it doesn't exist
    )
    // Perform the transfer
    const signature = await transfer(
      connection,
      senderKeypair,
      senderTokenAccount.address,
      receiverTokenAccount.address,
      senderKeypair.publicKey,
      TRANSFER_AMOUNT,
    )
    // Log the transaction signature
    console.log(`Transaction signature: ${signature}`)
    console.log(
      `You can verify the transaction on https://explorer.solana.com/tx/${signature}?cluster=devnet`,
    )
  } catch (error) {
    console.error('Error performing the transfer:', error)
  }
})()

Replace the value of the PRIVATE_KEY variable with your secure private key, which must be in Base58 format. Replace the value of the RECEIVER_PUBLIC_KEY variable with the receiver’s public key.

Save the Javascript file.

From the terminal command line, enter the following command to execute the code and transfer USDC:

node filename.js

You should see a similar output to the following example if your file executes successfully:

Transaction signature: dsLFw3rtDEWT2b3vpzournXspeTbeEZvzVAh3bmNaLzrqQB7nWrgj4rdh4j9gVb51p4mkDm1ivFUgkuC6Q7aehT
You can verify the transaction on https://explorer.solana.com/tx/dsLFw3rtDEWT2b3vpzournXspeTbeEZvzVAh3bmNaLzrqQB7nWrgj4rdh4j9gVb51p4mkDm1ivFUgkuC6Q7aehT?cluster=devnet

Check the status of your USDC transaction by visiting the Solana Devnet block explorer.

By completing this quickstart guide for USDC, you have started to use the essential skills of programmable money. You can adapt the script provided in this tutorial to enable real-world transactions and empower your own app development.

Now, you can begin to apply this knowledge to create frictionless financial experiences to empower users with seamless, secure global transactions.