# Payment Flow

Integrating QOOP with an existing website is extremely easy and can be achieved with a few simple steps. At a high level you want to achieve the following:

* POST transaction details to load the **QOOP *****PayExpress***
* Calculate a request hash to ensure transaction integrity
* Provide a URL which QOOP would post back the authorization response
* Query the transaction details directly from QOOP *Get Transaction Endpoint* to ensure the actual transaction amount was approved.

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**Step 1**\
`POST` is made with Transaction parameters to the QOOP payment endpoint. This is known as the beginning of the **payment leg**.

**Step 2**\
A `RESPONSE` is sent from the payment endpoint.

**Step 3**\
The merchant’s website initiates a `GET` request to the payment confirmation endpoint requesting the status of the concluded transaction. This is the beginning of the *getTransaction* leg.

**Step 4**\
&#x20;A `RESPONSE` is sent from the confirmation endpoint containing the status of the transaction.

The only requirement is to `POST` data to the QOOP server. The next section describes how to create this `POST`.