Sending USDC (or other ERC-20s)

npm install viem

import {encodeFunctionData, erc20Abi} from 'viem';

const recipientAddress = '0x...';
const amountToSend = 1; // Sender wants to send 1 USDC
const decimals = 6; // USDC has 6 decimals

const encodedData = encodeFunctionData({
  abi: erc20Abi,
  functionName: 'transfer',
  args: [recipientAddress, amountToSend * 10 ** decimals]
});

pip install eth-abi

from eth_abi.abi import encode
from eth_utils import function_signature_to_4byte_selector

usdc_address = "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913" # address on base
# Simplified ABI for the transfer function only
function_signature = "transfer(address,uint256)"
function_selector = function_signature_to_4byte_selector(function_signature)
decimals = 6
encoded_params = encode(
    ["address", "uint256"],
    [recipient_address, amount_to_send * 10**decimals],
)
data = "0x" + (function_selector + encoded_params).hex()

import { useSendTransaction } from '@privy-io/react-auth';
const { sendTransaction } = useSendTransaction();

const { hash } = await sendTransaction({
to: usdcContractAddress,
data: encodedData, // from the previous step
chainId: 8453, // Base's chainId
})

import {useEmbeddedEthereumWallet} from '@privy-io/expo';

const {wallets} = useEmbeddedEthereumWallet();
const wallet = wallets[0];

const provider = await wallet.getProvider();
const accounts = await provider.request({
    method: 'eth_requestAccounts',
});

// Send transaction (will be signed and populated)
const response = await provider.request({
    method: 'eth_sendTransaction',
    params: [
        {
            from: accounts[0],
            to: usdcContractAddress,
            data: encodedData, // from the previous step
        },
    ],
});

const usdcContractAddress = '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'; // on Base

const {hash} = await privy.walletApi.ethereum.sendTransaction({
walletId: 'insert-wallet-id',
caip2: 'eip155:8453', // Base's caip2
to: usdcContractAddress,
data: encodedData // from the previous step
})

tx = client.wallets.rpc(
    wallet_id=user.wallet_id,
    method="eth_sendTransaction",
    caip2="eip155:8453", # Base's caip2
    params={
        "transaction": {
            "to": usdc_address,
            "data": data,
        },
    },
)
return {"response": tx.data}

# response should look like this:
# {
# "caip2": "eip155:8453",
# "hash": "0x6443ca5b9ac1aeb31ec56e81e90699a08ef4f5d4b799855c5216a06a9f349f9e",
# "transaction_id": "kjrw3noey7m5q2l5tter50sl"
# }