x402

x402 HTTP Payments

HTTP payment gating using the x402 protocol with Hono middleware. A /protected-route requires a $0.10 payment on Base Sepolia — an Agent with a test wallet pays automatically.

What it demonstrates

• @x402/hono middleware — paymentMiddleware() gates any Hono route behind a price
• @x402/fetch — wrapFetchWithPayment(fetch) wraps fetch so the agent signs and pays automatically
• @x402/evm — EVM scheme registration for both client and server
• @callable — the agent exposes fetchProtectedRoute as a callable method
• useAgent + agent.call() — the React frontend triggers the paid fetch via WebSocket RPC

Running

Copy the environment file and fill in your keys:

cp .env.example .env

You need:

• SERVER_ADDRESS — an Ethereum address to receive payments (Base Sepolia testnet)
• CLIENT_TEST_PK — a private key for signing payments (test key only, get test funds from https://faucet.circle.com/)

Then:

npm install
npm start

Press "Fetch & Pay" to have the agent access the protected route and automatically pay.

How it works

Server: gating a route

import { paymentMiddleware, x402ResourceServer } from "@x402/hono";

app.use(
  paymentMiddleware(
    {
      "GET /protected-route": {
        accepts: [
          {
            scheme: "exact",
            price: "$0.10",
            network: "eip155:84532",
            payTo: process.env.SERVER_ADDRESS
          }
        ],
        description: "Access to premium content"
      }
    },
    resourceServer
  )
);

app.get("/protected-route", (c) => c.json({ message: "Thanks for paying!" }));

Agent: paying automatically

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";

export class PayAgent extends Agent<Env> {
  onStart() {
    const client = new x402Client();
    registerClientEvmScheme(client, { signer: account });
    this.fetchWithPay = wrapFetchWithPayment(fetch, client);
  }

  @callable()
  async fetchProtectedRoute() {
    const res = await this.fetchWithPay("/protected-route", {});
    return { text: await res.text(), isError: !res.ok };
  }
}

Compared to x402-mcp

This example gates HTTP endpoints using @x402/* libraries directly. The x402-mcp example gates MCP tools using the Agents SDK's withX402() / withX402Client() wrappers. Different protocols, different APIs.

Related examples

• x402-mcp — paid MCP tools using the Agents SDK's x402 integration