x402 Developer Quickstart

// Extract payment details
const {
  payTo,     // "0x02F68718AfbB3A8C4BDF906476CB444d7fe551Bd"
  amount,    // "20000" (= 0.02 USDC)
  currency,  // "USDC"
  network    // "base"
} = paymentReq;

// Convert amount to human-readable USDC
const usdcAmount = parseFloat(amount) / 1e6;
console.log(`Pay ${usdcAmount} USDC to ${payTo}`);

// Step 4: Construct payment proof
const paymentProof = {
  txHash: receipt.hash,           // Transaction hash from Step 3
  amount: paymentReq.amount       // Amount you paid
};

// Base64 encode the proof
const receiptHeader = btoa(JSON.stringify(paymentProof));

// Step 5: Retry request with payment receipt
const finalResponse = await fetch(
  'https://ai-chatbot.auramediastudios.workers.dev/api/x402/sentiment',
  {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'X-Payment-Receipt': receiptHeader
    },
    body: JSON.stringify({ text: 'I love this product!' })
  }
);

// Success! Get your data
const result = await finalResponse.json();
console.log('Result:', result);
// Output: { sentiment: "positive", score: 0.95, confidence: "high" }

import { ethers } from 'ethers';

async function callX402API() {
  // Configuration
  const API_URL = 'https://ai-chatbot.auramediastudios.workers.dev/api/x402/sentiment';
  const USDC_ADDRESS = '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913';
  const BASE_RPC = 'https://mainnet.base.org';

  // 1. Make initial request (get payment requirements)
  const initial = await fetch(API_URL, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ text: 'I love this!' })
  });

  if (initial.status !== 402) {
    throw new Error('Expected 402 Payment Required');
  }

  const paymentReq = await initial.json();
  console.log('Payment required:', paymentReq);

  // 2. Send USDC payment on Base L2
  const provider = new ethers.JsonRpcProvider(BASE_RPC);
  const wallet = new ethers.Wallet(process.env.PRIVATE_KEY, provider);
  const usdc = new ethers.Contract(
    USDC_ADDRESS,
    ['function transfer(address to, uint256 amount) returns (bool)'],
    wallet
  );

  const tx = await usdc.transfer(paymentReq.payTo, paymentReq.amount);
  const receipt = await tx.wait();
  console.log('Payment sent:', receipt.hash);

  // 3. Retry request with payment proof
  const paymentProof = { txHash: receipt.hash, amount: paymentReq.amount };
  const receiptHeader = btoa(JSON.stringify(paymentProof));

  const final = await fetch(API_URL, {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      'X-Payment-Receipt': receiptHeader
    },
    body: JSON.stringify({ text: 'I love this!' })
  });

  const result = await final.json();
  console.log('Result:', result);
  return result;
}

// Run it
callX402API().catch(console.error);