x402 결제 프로토콜

$ chainstream token info --chain sol --address So11111111111111111111111111111111111111112

[chainstream] No active subscription. Available plans:

   #  Plan       Price    Quota           Duration
   ── ────────── ──────── ──────────────── ────────
   1  nano       $5             500,000 CU  30 days
   2  starter    $199        10,000,000 CU  30 days
   3  pro        $699        50,000,000 CU  30 days

Select plan (1-3): 1

[chainstream] Choose payment method:
  1. x402 (USDC on Base/Solana)
  2. MPP Tempo (USDC.e on Tempo)

Select method (1-2): 1

[chainstream] Purchasing nano plan via x402...
[chainstream] Subscription activated: nano (expires: 2026-04-25T12:00:00.000Z)
[chainstream] API Key saved to config.

# ChainStream TEE 지갑 생성 (추천)
chainstream login

# 또는 원시 프라이빗 키 가져오기 (개발/테스트 전용)
chainstream wallet set-raw --chain base

npm install @x402/core @x402/evm @x402/svm @x402/fetch

import { createX402Fetch } from "@x402/fetch";
import { createWalletClient, http } from "viem";
import { base } from "viem/chains";
import { privateKeyToAccount } from "viem/accounts";

// 결제용 지갑 생성
const account = privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`);
const walletClient = createWalletClient({
  account,
  chain: base,
  transport: http(),
});

// x402 지원 fetch 생성
const x402Fetch = createX402Fetch({
  evm: { walletClient },
  autoApprove: true, // 프롬프트 없이 자동 결제
  maxAmount: "10.00", // 요청당 안전 한도
});

// 일반 fetch처럼 사용 — 402 결제가 자동으로 처리됩니다
const response = await x402Fetch(
  "https://api.chainstream.io/v1/tokens/analyze",
  {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ tokenAddress: "0x1234...abcd", chain: "ethereum" }),
  }
);

const data = await response.json();
console.log(data);

import { parsePaymentHeaders, createPaymentProof } from "@x402/core";
import { sendPayment } from "@x402/evm";

// 1. 초기 요청 보내기
const response = await fetch("https://api.chainstream.io/v1/tokens/analyze", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ tokenAddress: "0x1234...abcd" }),
});

if (response.status === 402) {
  // 2. 헤더에서 결제 세부 정보 파싱
  const payment = parsePaymentHeaders(response.headers);
  console.log(`Payment required: ${payment.amount} USDC on ${payment.chain}`);

  // 3. USDC 결제 전송
  const txHash = await sendPayment({
    walletClient,
    to: payment.address,
    amount: payment.amount,
    token: payment.token,
    memo: payment.memo,
  });

  // 4. 결제 서명과 함께 재시도
  const retryResponse = await fetch(
    "https://api.chainstream.io/x402/purchase?plan=nano",
    {
      headers: {
        "Payment-Signature": paymentSignature,
      },
    }
  );

  // 5. 응답에서 API 키 추출
  const result = await retryResponse.json();
  console.log("API key for future use:", result.apiKey);
  console.log("Expires at:", result.expiresAt);
}