This post gives an overview of the payment flow from the perspective of all parties involved, and introduces the key factors for a functioned integration.

The payment flow

CHECKOUT

1. You create a checkout via API invocation.
2. You receive a checkout URL in the API response, which contains a checkout URL.
3. You redirect your customer to the checkout URL.
4. The customer selects a payment method (card, Apple Pay, Alipay, etc.) and completes the payment.
5. The customer is redirected back to your website.
6. WooshPay sends an HTTP request whose HTTP body is an Event JSON object to your webhook URL to notify the status change.

SDK

1. Embed the code snippet into your checkout page.
2. Invoke the API to create a payment intent.
3. Use the payment intent ID to initiate the SDK widget, which eventually appears as a payment form.
4. The customer completes the payment.
5. WooshPay sends an HTTP request whose HTTP body is an Event JSON object to your webhook URL to notify the status change.

API

1. Invoke the API to create a payment intent.
2. Provide a payment method and confirm the payment intent.
3. WooshPay sends an HTTP request whose HTTP body is an Event JSON object to your webhook URL to notify the status change. (Step 1 and step 2 could be combined into one API invocation.)

Integration Key Factors

The APIs could be divided into three main types:

1. Transaction API: Includes functionalities such as payment intent creation, checkout creation, refund creation, etc.

2. Webhook: Register one or more webhooks to receive server-to-server calls and obtain post-payment details.

3. Query: Retrieve a transaction by its ID. It's recommended that you retrieve a transaction in case you fail to receive or process a webhook event call.

In order to make the payment flow complete and smooth, you should implement these three types separately.