Getting Started with x402

cURL Example

Step 1: Make initial request (returns 402)

curl -X POST https://ai-chatbot.auramediastudios.workers.dev/api/x402/sentiment \
  -H "Content-Type: application/json" \
  -d '{"text": "This product is amazing and works great!"}'

Response (HTTP 402):

{
  "error": "Payment required",
  "payment": {
    "amount_usdc": "0.02",
    "merchant_wallet": "0x02F68718AfbB3A8C4BDF906476CB444d7fe551Bd",
    "network": "Base L2",
    "chainId": 8453
  }
}

Step 2: Send USDC payment using your wallet (MetaMask, etc.)

Step 3: Retry with transaction hash

curl -X POST https://ai-chatbot.auramediastudios.workers.dev/api/x402/sentiment \
  -H "Content-Type: application/json" \
  -H "X-Payment-Receipt: $(echo '{"txHash":"0xYOUR_TX_HASH","amount":"20000"}' | base64)" \
  -d '{"text": "This product is amazing and works great!"}'

Success Response (HTTP 200):

{
  "sentiment": "positive",
  "confidence": 0.95,
  "text": "This product is amazing and works great!"
}

JavaScript Example

import { ethers } from 'ethers';

// Step 1: Make initial request
const response1 = await fetch(
  'https://ai-chatbot.auramediastudios.workers.dev/api/x402/sentiment',
  {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ text: 'Amazing product!' })
  }
);

// Step 2: Check for 402 and get payment details
if (response1.status === 402) {
  const { payment } = await response1.json();

  // Step 3: Send USDC payment on Base L2
  const provider = new ethers.BrowserProvider(window.ethereum);
  const signer = await provider.getSigner();

  const usdcContract = new ethers.Contract(
    '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913', // USDC on Base
    ['function transfer(address to, uint256 amount) returns (bool)'],
    signer
  );

  const amountInWei = ethers.parseUnits(payment.amount_usdc, 6); // USDC has 6 decimals
  const tx = await usdcContract.transfer(payment.merchant_wallet, amountInWei);
  await tx.wait(); // Wait for confirmation

  // Step 4: Retry with payment receipt
  const receipt = btoa(JSON.stringify({
    txHash: tx.hash,
    amount: amountInWei.toString()
  }));

  const response2 = await fetch(
    'https://ai-chatbot.auramediastudios.workers.dev/api/x402/sentiment',
    {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'X-Payment-Receipt': receipt
      },
      body: JSON.stringify({ text: 'Amazing product!' })
    }
  );

  const result = await response2.json();
  console.log(result); // { sentiment: 'positive', confidence: 0.95, ... }
}

Python Example

import requests
import base64
from web3 import Web3

# Step 1: Make initial request
response1 = requests.post(
    'https://ai-chatbot.auramediastudios.workers.dev/api/x402/sentiment',
    json={'text': 'Amazing product!'}
)

# Step 2: Check for 402 and get payment details
if response1.status_code == 402:
    payment = response1.json()['payment']

    # Step 3: Send USDC payment (using web3.py)
    w3 = Web3(Web3.HTTPProvider('https://mainnet.base.org'))

    # Your wallet private key (store securely!)
    account = w3.eth.account.from_key('YOUR_PRIVATE_KEY')

    # USDC contract on Base L2
    usdc_address = '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'
    usdc_abi = [{"constant": False, "inputs": [{"name": "to", "type": "address"}, {"name": "value", "type": "uint256"}], "name": "transfer", "outputs": [{"name": "", "type": "bool"}], "type": "function"}]
    usdc = w3.eth.contract(address=usdc_address, abi=usdc_abi)

    amount_wei = int(float(payment['amount_usdc']) * 1_000_000)  # USDC has 6 decimals

    tx = usdc.functions.transfer(
        payment['merchant_wallet'],
        amount_wei
    ).build_transaction({
        'from': account.address,
        'nonce': w3.eth.get_transaction_count(account.address),
        'gas': 100000,
        'gasPrice': w3.eth.gas_price
    })

    signed_tx = account.sign_transaction(tx)
    tx_hash = w3.eth.send_raw_transaction(signed_tx.raw_transaction)
    receipt = w3.eth.wait_for_transaction_receipt(tx_hash)

    # Step 4: Retry with payment receipt
    payment_receipt = base64.b64encode(
        f'{{"txHash":"{tx_hash.hex()}","amount":"{amount_wei}"}}'.encode()
    ).decode()

    response2 = requests.post(
        'https://ai-chatbot.auramediastudios.workers.dev/api/x402/sentiment',
        json={'text': 'Amazing product!'},
        headers={'X-Payment-Receipt': payment_receipt}
    )

    print(response2.json())  # {'sentiment': 'positive', 'confidence': 0.95, ...}