setup-x402-client

Add x402 Client to Your Project

Set up automatic x402 payment handling so your application can call paid APIs.

This command builds an independent @dexterai/x402 SDK client. It is not the OpenDexter MCP runtime, does not inherit an OpenDexter OAuth bearer or grant, and must never be used as a fallback for a disconnected or unavailable OpenDexter account-bound tool.

Steps

1. Install the SDK:

npm install @dexterai/[email protected] @dexterai/[email protected]

1. Create an application-owned payment helper. Add this file to your project:

// lib/x402.ts
import { createKeypairWallet, payAndFetch } from '@dexterai/x402/client';

const solana = await createKeypairWallet(process.env.SOLANA_PRIVATE_KEY!);

export async function x402Fetch(url: string, init: RequestInit = {}) {
  const result = await payAndFetch(url, init, { solana }, {
    maxAmountAtomic: '1000000', // Safety limit: max $1.00 per request
    solanaRpcUrl: process.env.SOLANA_RPC_URL,
  });
  if (!result.ok) {
    throw new Error(`${result.reason}: ${result.detail ?? ''}`);
  }
  if (!result.response) {
    throw new Error('Payment settled, but the merchant returned no response');
  }
  return result.response;
}

1. Add your private key to .env:

SOLANA_PRIVATE_KEY=your-base58-private-key-here

1. Use it anywhere in your application:

import { x402Fetch } from './lib/x402';

const response = await x402Fetch('https://x402-api.example.com/data');
const data = await response.json();

1. For dual-chain support (Solana + EVM), add viem and an EVM wallet:

npm install viem

import { createEvmKeypairWallet } from '@dexterai/x402/client';

const wallets = {
  solana,
  evm: await createEvmKeypairWallet(process.env.EVM_PRIVATE_KEY!),
};

V6 has no wrapFetch or createX402Client export. Use payAndFetch, and do not automatically retry payment_unconfirmed: the first payment may already have settled.

Verify

Test with the Dexter test endpoint: