@billmyagent/payments-core

x402 payment client for billmyagent. It pays HTTP 402 Payment Required challenges automatically using the official x402 libraries: it signs an EIP-3009 transferWithAuthorization with your wallet and lets the facilitator settle it on-chain. Framework-agnostic — wrap it with @billmyagent/payments-react, -vue, or -elements.

Install

npm install @billmyagent/payments-core

Pay an x402-gated API

import { PaymentClient, createSigner } from '@billmyagent/payments-core';

// Build a signer from a private key (server/agent). Never ship a real key to a browser.
const signer = await createSigner('base', process.env.PRIVATE_KEY!);

const client = new PaymentClient({ signer });

// `client.http` is an axios instance; any 402 it hits is paid and the request retried.
const res = await client.http.get('https://api.example.com/paid-resource');
console.log(res.data);

In a browser, pass a viem wallet client backed by the user's wallet instead of a private-key signer.

Merchant account methods

Pass an apiKey (and authToken JWT for /merchant/*) to use the billmyagent REST API:

const client = new PaymentClient({ apiKey: process.env.BMA_API_KEY!, authToken: jwt });

await client.getPayoutSettings();
await client.updatePayoutSettings({ base_address: '0x…' });
await client.getFees();
await client.listInvoices();

Also available: createPayment, getPayment, verifyPayment, settlePayment, listPayments.

What's in the box

• PaymentClient — pays x402 challenges (client.http) and wraps the merchant REST API
• createSigner / Signer — re-exported from x402-axios for building wallet signers
• Types: Payment, CreatePaymentRequest, PayoutSettings, FeeRow, FeeInvoice, and the re-exported AxiosRequestConfig / AxiosResponse

Supported networks

EVM only, exact scheme: Base, Ethereum, Polygon.

Development

# from sdk/core/
npm install
npm run build

License

Apache 2.0 — see LICENSE.