x402 Payment Protocol

$ 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.

# Create a ChainStream TEE wallet (recommended)
chainstream login

# Or import a raw private key (dev/testing only)
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";

// Create a wallet for payments
const account = privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`);
const walletClient = createWalletClient({
  account,
  chain: base,
  transport: http(),
});

// Create an x402-enabled fetch
const x402Fetch = createX402Fetch({
  evm: { walletClient },
  autoApprove: true, // auto-pay without prompting
  maxAmount: "10.00", // safety cap per request
});

// Use it like normal fetch -- 402 payments are handled automatically
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. Make the initial request
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. Parse payment details from headers
  const payment = parsePaymentHeaders(response.headers);
  console.log(`Payment required: ${payment.amount} USDC on ${payment.chain}`);

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

  // 4. Retry with payment signature
  const retryResponse = await fetch(
    "https://api.chainstream.io/x402/purchase?plan=nano",
    {
      headers: {
        "Payment-Signature": paymentSignature,
      },
    }
  );

  // 5. Extract the API key from the response
  const result = await retryResponse.json();
  console.log("API key for future use:", result.apiKey);
  console.log("Expires at:", result.expiresAt);
}