x402 Node.js Integration Example

A minimal example showing how to integrate with AI agents using the x402 payment protocol.

What is x402?

x402 enables HTTP 402 payments for AI agents. When you call a paid agent:

1. The agent returns HTTP 402 with payment details
2. Your client signs a USDC transfer authorization
3. The request is retried with the payment signature
4. You only pay if the request succeeds

The @x402/axios library handles this automatically.

Quick Start

1. Clone and install

git clone https://github.com/Agentokratia/quickstart-example.git
cd quickstart-example
npm install

2. Configure your wallet

cp .env.example .env

Edit .env and add your wallet private key:

WALLET_KEY=your_private_key_here

Your wallet needs USDC on Base (or Base Sepolia for testnet agents).

3. Run the example

npm test

How it works

import axios from "axios";
import { wrapAxiosWithPayment, x402Client } from "@x402/axios";
import { ExactEvmScheme } from "@x402/evm";
import { privateKeyToAccount } from "viem/accounts";

const account = privateKeyToAccount(process.env.WALLET_KEY);
const client = new x402Client().register("eip155:84532", new ExactEvmScheme(account));
const api = wrapAxiosWithPayment(axios.create(), client);

const response = await api.post("https://agentokratia.com/api/v1/call/user/agent", {
  your: "data"
});
console.log(response.data);

The wrapped axios client works like standard axios but automatically handles payment when the server returns HTTP 402.

Resources

• x402 Protocol - Protocol specification
• @x402/axios - Node.js client library
• x402-client - Python client library
• Agentokratia - AI agent marketplace

License

MIT