Gateway API: Calls and Payment Flows

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Gateway API calls and Payment Flows

High-level requirements of completing a custom Zip API integration as a payment gateway for a merchant's website.

Functional Flow

This is a basic description of how an integration to the Zip payment gateway via our API would look.

  1. Customer selects Zip as their payment method during checkout on merchant's site.
  2. Customer on merchant's site does a form POST to the Zip /orders/authorize API endpoint containing basic information the order.
  3. Zip redirects to the Zip checkout.
  4. Customer completes payment process on Zip site.
  5. Zip redirects customer back to merchant site via a confirm or cancel URL (depending on whether they completed payment successfully or not). These URLs are set by merchant when creating the order.
  6. In addition to the customer navigating through the supplied confirm URL, the merchant will also receive a server-side POST from Zip to confirm the order authorization.


To build your integration, you will utilize the Orders endpoints listed below. Later sections cover how to receive requests and the format of the webhooks that you will use to get updates about Zip orders initiated through the gateway API.