📚 DOCUMENTATION

🔍 WHAT IS S402 SCAN?

S402 Scan is a comprehensive ecosystem explorer for the S402 payment protocol on BNB Chain. It provides real-time analytics, transaction monitoring, and a marketplace for AI agents that use micropayments to access external APIs and services.

🚀 GETTING STARTED

💰 AGENTIC FEE BUYBACKS TO $SORA

The S402 ecosystem features a unique tokenomics model that creates value for $SORA token holders:

🌐 OPEN SOURCE & PERMISSIONLESS

S402 is an open source payment protocol that anyone can use, modify, and implement:

🛠️ TECHNICAL GUIDE: BUILD YOUR OWN S402 SERVER

Anyone can create S402-enabled services that accept micropayments for API access. This guide shows you how to implement the S402 protocol in your own applications.

// Contract addresses
const S402_FACILITATOR = "0x75c8CCD195F7B5Fb288B107B45FaF9a1289d7Df1";
const USD1_TOKEN = "0x8d0D000Ee44948FC98c9B98A4FA4921476f08B0d";
const BNB_CHAIN_ID = 56;

import { ethers } from "ethers";

async function createPaymentSignature(sender, recipient, amount) {
  const provider = new ethers.BrowserProvider(window.ethereum);
  const signer = await provider.getSigner();
  const nonce = Date.now(); // Unique nonce for replay protection
  const deadline = Math.floor(Date.now() / 1000) + 3600; // 1 hour validity
  
  // EIP-712 domain
  const domain = {
    name: "S402PaymentFacilitator",
    version: "3",
    chainId: BNB_CHAIN_ID,
    verifyingContract: S402_FACILITATOR
  };
  
  // Payment types
  const types = {
    Payment: [
      { name: "sender", type: "address" },
      { name: "recipient", type: "address" },
      { name: "amount", type: "uint256" },
      { name: "nonce", type: "uint256" },
      { name: "deadline", type: "uint256" }
    ]
  };
  
  // Payment data
  const value = {
    sender,
    recipient,
    amount: ethers.parseUnits(amount.toString(), 18), // USD1 has 18 decimals
    nonce,
    deadline
  };
  
  // Sign the message
  const signature = await signer.signTypedData(domain, types, value);
  return { signature, nonce, deadline };
}

import { ethers } from "ethers";

async function verifyAndSettlePayment(paymentData) {
  const { sender, recipient, amount, nonce, deadline, signature } = paymentData;
  
  // 1. Verify signature is valid
  const domain = { /* same as client-side */ };
  const types = { /* same as client-side */ };
  const value = { sender, recipient, amount, nonce, deadline };
  
  const recoveredAddress = ethers.verifyTypedData(domain, types, value, signature);
  if (recoveredAddress.toLowerCase() !== sender.toLowerCase()) {
    throw new Error("Invalid signature");
  }
  
  // 2. Check amount is correct
  const expectedAmount = ethers.parseUnits("0.02", 18); // $0.02 for this service
  if (amount !== expectedAmount) {
    throw new Error("Incorrect payment amount");
  }
  
  // 3. Check recipient is your server wallet
  if (recipient.toLowerCase() !== YOUR_SERVER_WALLET.toLowerCase()) {
    throw new Error("Invalid recipient");
  }
  
  // 4. Check deadline hasn't passed
  if (Date.now() / 1000 > deadline) {
    throw new Error("Payment expired");
  }
  
  // 5. Check nonce hasn't been used (prevent replay attacks)
  if (await isNonceUsed(nonce)) {
    throw new Error("Nonce already used");
  }
  
  // 6. Settle payment on-chain via S402 Facilitator
  const provider = new ethers.JsonRpcProvider("https://bsc-dataseed.binance.org");
  const wallet = new ethers.Wallet(SERVER_PRIVATE_KEY, provider);
  const facilitator = new ethers.Contract(S402_FACILITATOR, ABI, wallet);
  
  const tx = await facilitator.settlePayment(
    sender, recipient, amount, nonce, deadline, signature
  );
  await tx.wait();
  
  // 7. Mark nonce as used
  await markNonceUsed(nonce);
  
  return true; // Payment verified!
}

import express from "express";
import cors from "cors";

const app = express();
app.use(cors());
app.use(express.json());

// Your paid API endpoint
app.post("/api/generate-image", async (req, res) => {
  try {
    // Extract payment data from request
    const { payment, prompt } = req.body;
    
    // Verify payment
    await verifyAndSettlePayment(payment);
    
    // Payment verified! Process the request
    const imageUrl = await generateImage(prompt);
    
    res.json({ success: true, imageUrl });
  } catch (error) {
    res.status(402).json({
      success: false,
      error: "Payment Required",
      message: error.message
    });
  }
});

app.listen(3001, () => console.log("S402 server running"));

INSERT INTO s402_tools (name, price, recipient_address, icon_url, category)
VALUES (
  'My Amazing Service',
  '0.05', -- Price in USD1
  '0xYourServerWallet...',
  'https://example.com/icon.jpg',
  'media' -- or 'data', 'compute', etc.
);

⚡ KEY FEATURES

❓ FREQUENTLY ASKED QUESTIONS