Quickstart: Set up and transfer USDC on Starknet

This quickstart guide helps you write a standalone index.js script that checks your USDC balance and sends a test transfer on the Starknet Sepolia. It’s designed for developers looking to quickly get hands-on with USDC on Starknet.

Prerequisites

Before you begin, make sure you have:

Installed Node.js v18+ and npm, which comes with Node.js.
- Created a free Alchemy account to get an API key for Starknet RPC access.
Created a Starknet Sepolia wallet:
- Braavos wallet (Recommended) - Best compatibility for programmatic transactions. Alternatives: Argent X (Note: Guardian-protected accounts may require additional configuration).
- Request testnet STRK from the faucet.
- Request testnet USDC from the faucet

USDC contract address

Use the following contract address for USDC on the Starknet Sepolia Testnet: USDC contract: 0x0512feAc6339Ff7889822cb5aA2a86C848e9D392bB0E3E237C008674feeD8343

Part 1: Set up your project

Follow these steps to install dependencies and set up your script environment.

1.1. Initialize a project

Create a new directory and initialize it with npm:

mkdir usdc-starknet-script
cd usdc-starknet-script
npm init -y
npm pkg set type=module

1.2. Install required dependencies

Install starknet (version 8.x) and dotenv:

npm install starknet@^8.9.0 dotenv

1.3. Create your `.env` file

In the project root, create a .env file and add the following values:

Text

# Your Starknet account address (felt252 format with 0x prefix)
ACCOUNT_ADDRESS=0x<YOUR_ACCOUNT_ADDRESS>

# Your private key (felt252 format with 0x prefix)
PRIVATE_KEY=0x<YOUR_PRIVATE_KEY>

# The address you want to send USDC to (felt252 format with 0x prefix)
RECIPIENT_ADDRESS=0x<RECIPIENT_ADDRESS>

Important: On Starknet, you need both your account address and private key because Starknet uses account abstraction. Your private key alone doesn’t derive your account address.

Part 2: Build your script

Create a file named index.js. You’ll build your script step-by-step in the following sections.

2.1. Import libraries and define constants

In index.js, start by importing dependencies and setting up the chain and token configuration:

import "dotenv/config";
import { Account, Contract, RpcProvider, uint256 } from "starknet";

const provider = new RpcProvider({
  nodeUrl:
    "https://starknet-sepolia.g.alchemy.com/starknet/version/rpc/v0_10/YOUR_API_KEY",
});

const USDC_ADDRESS =
  "0x053b40A647CEDfca6cA84f542A0fe36736031905A9639a7f19A3C1e66bFd5080";
const USDC_DECIMALS = 6;

const USDC_ABI = [
  {
    name: "balance_of",
    type: "function",
    inputs: [
      {
        name: "account",
        type: "core::starknet::contract_address::ContractAddress",
      },
    ],
    outputs: [{ name: "balance", type: "core::integer::u256" }],
    state_mutability: "view",
  },
  {
    name: "transfer",
    type: "function",
    inputs: [
      {
        name: "recipient",
        type: "core::starknet::contract_address::ContractAddress",
      },
      { name: "amount", type: "core::integer::u256" },
    ],
    outputs: [{ name: "success", type: "core::bool" }],
    state_mutability: "external",
  },
];

Replace YOUR_API_KEY with your Alchemy API key from alchemy.com/starknet

Learn more: Why use a minimal ABI?

This ABI includes only the two methods needed for this script:

balanceOf(address) to check the token balance.
transfer(to, amount) to send USDC.

This makes the ABI compact and easier to understand. Using a minimal ABI:

Reduces complexity by excluding unrelated functions.
Speeds up onboarding for new developers.
Avoids unnecessary contract data that would be unused in this context.

Note: Starknet uses Cairo, so function names follow snake_case convention (for example, balance_of instead of balanceOf).

2.2. Set up Starknet account and contract

Set up the Starknet account and contract instances:

const account = new Account({
  provider,
  address: process.env.ACCOUNT_ADDRESS,
  signer: process.env.PRIVATE_KEY,
});

const usdcContract = new Contract({
  abi: USDC_ABI,
  address: USDC_ADDRESS,
  providerOrAccount: account,
});

Learn more: account abstraction on Starknet

Unlike Ethereum, Starknet uses account abstraction by default:

Every wallet is a smart contract (not an EOA).
You need both the account address AND private key.
The private key signs transactions, but the account contract validates them.

This enables features like:

Multi-signature wallets
Social recovery
Custom transaction validation logic
Gasless transactions (meta-transactions)

2.3. Check balance and send USDC

Now add the logic to check your balance and send tokens:

(async () => {
  try {
    const balanceResult = await usdcContract.balance_of(account.address);
    const balance = uint256.uint256ToBN(balanceResult.balance);
    const balanceFormatted = Number(balance) / 10 ** USDC_DECIMALS;

    console.log("Sender:", account.address);
    console.log("Recipient:", process.env.RECIPIENT_ADDRESS);
    console.log("USDC balance:", balanceFormatted.toFixed(2));

    const amount = 0.1;
    const amountU256 = uint256.bnToUint256(amount * 10 ** USDC_DECIMALS);

    const tx = await usdcContract.transfer(
      process.env.RECIPIENT_ADDRESS,
      amountU256,
    );

    await provider.waitForTransaction(tx.transaction_hash);

    console.log("Transfer successful!");
    console.log("Tx hash:", tx.transaction_hash);
    console.log(
      "Explorer:",
      `https://sepolia.voyager.online/tx/${tx.transaction_hash}`,
    );
  } catch (err) {
    console.error("Transfer failed:", err.message || err);
    process.exit(1);
  }
})();

Part 3: Run your script

To run your script, use the following command:

node index.js

Sample output

If the script runs successfully, your terminal will print a transaction summary like this:

Text

Sender: 0x025c0197095dff110edc45fd171c498b167fbe1c803294d22483064b0207a465
Recipient: 0x043ccE75C31169455E07B19265024107B067700BB711DEeffecE32766d7bf5c7
USDC balance: 10.00
Transfer successful!
Tx hash: 0xabc123def456789...
Explorer: https://sepolia.voyager.online/tx/0xabc123def456789...

You can open the explorer link in your browser to view the transaction on Voyager.

Additional notes

Testnet only: This guide runs on the Starknet Sepolia testnet. Tokens and transfers here are not real and hold no value.
Security best practices: Always store sensitive data like private keys in environment variables. Never hardcode or commit .env files to version control. Add .env to your .gitignore file.
Gas fees: Starknet requires STRK tokens for gas. Be sure to request testnet STRK from the faucet so your transactions can be processed.
Lightweight ABI: The ABI used here is minimal. It includes only the functions necessary for balance checks and transfers, which keeps the script lean.
V3 transactions: Starknet.js v8 uses V3 transactions by default, which include resource bounds for L1 gas, L2 gas, and L1 data gas.
Wallet compatibility: Braavos wallet is recommended for programmatic transactions. Argent accounts with guardians may require additional configuration.

​Prerequisites

​USDC contract address

​Part 1: Set up your project

​1.1. Initialize a project

​1.2. Install required dependencies

​1.3. Create your .env file

​Part 2: Build your script

​2.1. Import libraries and define constants

​2.2. Set up Starknet account and contract

​2.3. Check balance and send USDC

​Part 3: Run your script

​Sample output

​Additional notes

Prerequisites

USDC contract address

Part 1: Set up your project

1.1. Initialize a project

1.2. Install required dependencies

1.3. Create your `.env` file

Part 2: Build your script

2.1. Import libraries and define constants

2.2. Set up Starknet account and contract

2.3. Check balance and send USDC

Part 3: Run your script

Sample output

Additional notes