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
This entity — PayAI — is deployed and activley supporting SKALE. These are 3rd party services that may have their own terms and conditions and privacy polices. Use these services at your own risk. AI and agents is a highly experimental space; the 3rd party software solutions may have bugs or be unaudited. You and your agents and your customers use all 3rd party services chosen at your own risk and per their terms.
