PayAI is a hosted facilitator service that simplifies x402 payment processing. Instead of running your own facilitator infrastructure, you can use PayAI’s endpoints to handle payment verification and settlement.
Prerequisites
- Node.js and npm installed
- A SKALE Chain endpoint
- Basic understanding of x402 protocol
Configuration
Environment Variables
Create a .env file with PayAI configuration:
# PayAI Facilitator URL
FACILITATOR_URL=https://facilitator.payai.example.com
# Facilitator Router Address
RECEIVING_ADDRESS=0xFacilitatorRouterAddress
# Payment token configuration
PAYMENT_TOKEN_ADDRESS=0x61a26022927096f444994dA1e53F0FD9487EAfcf
PAYMENT_TOKEN_NAME="Axios USD"
# SKALE network configuration
NETWORK_CHAIN_ID=324705682
# Server port
PORT=3000
Integration with PayAI
Server Setup
Client Setup
import { Hono } from "hono";
import { serve } from "@hono/node-server";
import { paymentMiddleware, x402ResourceServer } from "@x402/hono";
import { ExactEvmScheme } from "@x402/evm/exact/server";
import { HTTPFacilitatorClient } from "@x402/core/server";
import type { Network } from "@x402/core/types";
import "dotenv/config";
const app = new Hono();
async function main() {
// Point to PayAI facilitator
const facilitatorUrl = process.env.FACILITATOR_URL!;
const receivingAddress = process.env.RECEIVING_ADDRESS as `0x${string}`;
const paymentTokenAddress = process.env.PAYMENT_TOKEN_ADDRESS as `0x${string}`;
const paymentTokenName = process.env.PAYMENT_TOKEN_NAME || "Axios USD";
const networkChainId = process.env.NETWORK_CHAIN_ID || "324705682";
const network: Network = `eip155:${networkChainId}`;
// Initialize PayAI facilitator client
const facilitatorClient = new HTTPFacilitatorClient({
url: facilitatorUrl
});
const resourceServer = new x402ResourceServer(facilitatorClient);
resourceServer.register("eip155:*", new ExactEvmScheme());
// Apply payment middleware
app.use(
paymentMiddleware(
{
"GET /api/data": {
accepts: [
{
scheme: "exact",
network: network,
payTo: receivingAddress,
price: {
amount: "10000", // 0.01 tokens
asset: paymentTokenAddress,
extra: {
name: paymentTokenName,
version: "1",
},
},
},
],
description: "Premium data access",
mimeType: "application/json",
},
},
resourceServer
)
);
// Protected endpoint
app.get("/api/data", (c) => {
return c.json({
message: "Premium data unlocked via PayAI!",
timestamp: new Date().toISOString(),
});
});
const port = Number(process.env.PORT) || 3000;
serve({ fetch: app.fetch, port }, () => {
console.log(`Server running on http://localhost:${port}`);
console.log(`Using PayAI facilitator: ${facilitatorUrl}`);
});
}
main().catch(console.error);
import { x402Client, x402HTTPClient } from "@x402/core/client";
import { ExactEvmScheme } from "@x402/evm";
import { privateKeyToAccount } from "viem/accounts";
import "dotenv/config";
async function main() {
// Setup wallet
const account = privateKeyToAccount(
process.env.PRIVATE_KEY as `0x${string}`
);
// Create x402 client
const evmScheme = new ExactEvmScheme(account);
const coreClient = new x402Client().register("eip155:*", evmScheme);
const httpClient = new x402HTTPClient(coreClient);
// Access PayAI-protected resource
const url = "http://localhost:3000/api/data";
const response = await fetch(url);
if (response.status === 402) {
console.log("Payment required, processing via PayAI...");
const responseBody = await response.json();
const paymentRequired = httpClient.getPaymentRequiredResponse(
(name: string) => response.headers.get(name),
responseBody
);
const paymentPayload = await httpClient.createPaymentPayload(
paymentRequired
);
const paymentHeaders = httpClient.encodePaymentSignatureHeader(
paymentPayload
);
const paidResponse = await fetch(url, {
headers: { ...paymentHeaders },
});
const data = await paidResponse.json();
console.log("Data received:", data);
}
}
main();
Troubleshooting
Connection Issues
If you cannot connect to PayAI:
- Verify the facilitator URL is correct
- Check network connectivity
- Ensure API credentials are valid
- Review firewall settings
Payment Failures
Common causes and solutions:
| Issue | Solution |
|---|
| Invalid signature | Verify wallet configuration and signing |
| Insufficient balance | Ensure payer has enough tokens |
| Network mismatch | Check chain ID matches configuration |
| Expired authorization | Increase maxTimeoutSeconds |
Next Steps
Resources
PayAI is a third-party service. Contact the PayAI team for access, pricing, and support information. The URLs in this guide are placeholders and will be updated when the service is publicly available.
