Headless SDK

Use @sigworld/sdk when the merchant needs a custom payment UI or custom orchestration. For the standard hosted experience, use SDK UI instead.

Server session creation

The SDK can create checkout sessions from a merchant server with a server-only Merchant API Key:

import { SigWorldSDK } from '@sigworld/sdk';

const sixpay = new SigWorldSDK({
  merchantApiKey: process.env.SIXPAY_CHECKOUT_API_KEY,
});

const session = await sixpay.checkout.createCheckoutSession({
  tenantId: process.env.SIXPAY_TENANT_ID!,
  merchantOrderId: order.id,
  items: [{
    lineItemId: orderItem.id,
    skuId: orderItem.sku,
    quantity: orderItem.quantity,
    unitAmount: orderItem.unitAmount.toFixed(2),
  }],
});

Do not instantiate this server configuration in browser code.

Direct compatibility flow

A custom flow without a merchant backend may use merchantTenantId, amountUSD, and optional merchantOrderId to resolve checkout data. This is a compatibility fallback, not the preferred path for existing order systems. It cannot use server-authoritative item promotion pricing. When passing both merchantOrderId and pre-encoded hexadecimal intentMeta, intentMeta takes precedence. If neither is supplied, payment can still proceed but webhook order.merchantOrderId is null.

Overview

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Reference

Server session creation

Direct compatibility flow

​Server session creation

​Direct compatibility flow

Server session creation

Direct compatibility flow