General API
General information for integrating with the Hipay API.
📄️ Create an invoice
Creates a payment invoice with the provided amount information. Upon successful creation, a unique `checkoutId` is returned, which can be used for payment transactions.
📄️ Invoice reference
Queries the status of a transaction using the invoice number (checkoutId).
📄️ Cancel an invoice
Use this API to cancel a payment invoice from the POS system. A canceled invoice cannot be paid. Paid invoices cannot be canceled.
📄️ Refund a payment transaction
Allows for refunding a transaction due to system errors or user refund requests. Refunds can only be processed on the same day. Transactions made at 23:59 cannot be refunded at 00:00.
📄️ Make payment - DEEPLINK
The payment invoice ID created via the above API will be retrieved and a Hipay app Deeplink will be invoked. 
📄️ Payment response WEBHOOK
After a payment is successfully completed, Hipay will send a payment notification to the merchant’s registered WEBHOOK_URL via a GET request with a 60-second timeout. If the response to that request is not successful (HTTP code 200), Hipay will consider the notification as failed and will resend it according to the following intervals: