@libertai/x402

x402 utilities that handle payments automatically for LibertAI services

Install

npm install @libertai/x402

Usage with OpenAI SDK

import { wrapFetchWithPayment } from "@libertai/x402";
import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.libertai.io/v1",
  apiKey: "x402",
  fetch: wrapFetchWithPayment(process.env.PRIVATE_KEY as `0x${string}`),
});

const response = await client.chat.completions.create({
  model: "qwen3-coder-next",
  messages: [{ role: "user", content: "Hello!" }],
});

console.log(response.choices[0].message.content);

Set apiKey to "x402" — the wrapper strips this dummy value before sending requests. Real API keys (any other value) are preserved.

Usage with plain fetch

import { wrapFetchWithPayment } from "@libertai/x402";

const fetchWithPayment = wrapFetchWithPayment("0x...");

const response = await fetchWithPayment(
  "https://api.libertai.io/v1/chat/completions",
  {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({
      model: "qwen3-coder-next",
      messages: [{ role: "user", content: "Hello!" }],
    }),
  },
);

How it works

1. Makes the request normally
2. If the server responds with 402, reads PaymentRequirements from the response body
3. Signs an EIP-712 typed data message (TransferWithAuthorization on Base) using the provided private key
4. Retries the request with the signed payment in the X-PAYMENT header

License

MIT