x402 SDK

The x402 SDK enables direct-to-protocol AI payments using crypto wallets. No API keys required - payments are handled via HTTP 402 status codes and on-chain signatures.

Installation

npm install @merit-systems/ai-x402

pnpm add @merit-systems/ai-x402

yarn add @merit-systems/ai-x402

bun add @merit-systems/ai-x402

Quick Start

import { createX402OpenAI } from '@merit-systems/ai-x402';
import { generateText } from 'ai';
import { CdpClient } from '@coinbase/cdp-sdk';
import { toAccount } from 'viem/accounts';

// Create wallet using Coinbase Developer Platform
const cdp = new CdpClient({
  apiKeyId: process.env.CDP_API_KEY_ID,
  apiKeySecret: process.env.CDP_API_KEY_SECRET,
  walletSecret: process.env.CDP_WALLET_SECRET,
});

const account = await cdp.evm.getOrCreateAccount({
  name: process.env.CDP_WALLET_OWNER,
});

const walletClient = toAccount(account);

// Create OpenAI provider with automatic x402 payment handling
const openai = createX402OpenAI(walletClient);

// Use with Vercel AI SDK
const { text } = await generateText({
  model: openai('gpt-4o'),
  prompt: 'Hello world'
});

How It Works

First request returns HTTP 402 with payment requirements
SDK creates payment signature using your wallet
SDK retries request with x-payment header
Request succeeds and payment settles on-chain

API

`createX402OpenAI(walletClient, baseRouterUrl?)`

Creates an OpenAI provider that handles x402 payments automatically.

Parameters:

walletClient - x402 wallet signer
baseRouterUrl - Optional router URL (default: https://echo.router.merit.systems)

Returns: OpenAI provider compatible with Vercel AI SDK

Custom Router

const openai = createX402OpenAI(
  walletClient,
  'https://your-router.com'
);

Overview