x402 on SKALE

x402 is HTTP 402 protocol for AI agent payments. Zero gas fees make SKALE ideal for micropayments.

What is x402?

• Extends HTTP with native payment capabilities using 402 Payment Required
• Paywalled Resources: Protect APIs behind payments
• Autonomous Payments: Agents automatically pay for resources
• ERC-3009 Compatibility: Uses TransferWithAuthorization for gasless payments

Facilitators

Use a facilitator to handle payments - don't run your own:

Service	URL	Notes
PayAI	https://facilitator.payai.network	Recommended
Corbits	https://corbits.dev	Developer-focused
RelAI	https://api.relai.fi	Marketplace
Kobaru	https://kobaru.io	Enterprise

Payment Tokens on SKALE

Token	Address	Decimals
Bridged USDC	0x2e08028E3C4c2356572E096d8EF835cD5C6030bD	6
Axios USD	0x61a26022927096f444994dA1e53F0FD9487EAfcf	6

Network IDs

Format: eip155:CHAIN_ID

Chain	Chain ID	x402 Network ID
SKALE Base Sepolia	324705682	eip155:324705682
SKALE Base	1187947933	eip155:1187947933

Install

npm install @x402/core @x402/evm @x402/hono

Server Setup

import { Hono } from "hono";
import { paymentMiddleware, x402ResourceServer } from "@x402/hono";
import { ExactEvmScheme } from "@x402/evm/exact/server";
import { HTTPFacilitatorClient } from "@x402/core/server";

const client = new HTTPFacilitatorClient({ url: "https://facilitator.payai.network" });
const server = new x402ResourceServer(client);
server.register("eip155:*", new ExactEvmScheme());

const app = new Hono();

app.use(paymentMiddleware({
    "GET /api/premium": {
        accepts: [{
            scheme: "exact",
            network: "eip155:324705682",
            payTo: "0xYourReceivingAddress",
            price: { 
                amount: "10000",  // 0.01 USDC (6 decimals)
                asset: "0x2e08028E3C4c2356572E096d8EF835cD5C6030bD"
            }
        }]
    }
}, server));

app.get("/api/premium", (c) => c.json({ data: "premium!" }));

Multiple Endpoints

app.use(paymentMiddleware({
    "GET /api/basic": {
        accepts: [{
            scheme: "exact",
            network: "eip155:324705682",
            payTo: "0xYourAddress",
            price: { amount: "1000", asset: "0x..." }  // 0.001 USDC
        }]
    },
    "GET /api/premium": {
        accepts: [{
            scheme: "exact",
            network: "eip155:324705682",
            payTo: "0xYourAddress",
            price: { amount: "10000", asset: "0x..." }  // 0.01 USDC
        }]
    }
}, server));

Agent Client

import { x402Client, x402HTTPClient } from "@x402/core/client";
import { ExactEvmScheme } from "@x402/evm";
import { privateKeyToAccount } from "viem/accounts";

const account = privateKeyToAccount(process.env.PRIVATE_KEY as `0x${string}`);
const httpClient = new x402HTTPClient(
    new x402Client().register("eip155:*", new ExactEvmScheme(account))
);

async function accessPaidResource(url: string) {
    const response = await fetch(url);
    
    if (response.status === 402) {
        const responseBody = await response.json();
        const paymentRequired = httpClient.getPaymentRequiredResponse(
            (name) => response.headers.get(name),
            responseBody
        );
        
        const paymentPayload = await httpClient.createPaymentPayload(paymentRequired);
        const paymentHeaders = httpClient.encodePaymentSignatureHeader(paymentPayload);
        
        const paidResponse = await fetch(url, { headers: paymentHeaders });
        return paidResponse.json();
    }
    
    if (!response.ok) {
        throw new Error(`Request failed: ${response.status}`);
    }
    
    return response.json();
}

Price Calculation

Amount is in token decimals (USDC = 6):

Amount	USDC
100	$0.0001
1000	$0.001
10000	$0.01
1000000	$1.00

Use Cases

• Autonomous Service Access: Agents pay for API calls, data feeds, AI services
• Monetize Agent Services: Protect AI endpoints with payments
• Multi-Agent Economies: Agent-to-agent payments for services

Reference: x402 Docs