The following diagram describes the steps involved in making a payment using Amazon FPS.
In the diagram, the caller (the fictitious company DigitalDownload) is also the recipient.
In the diagram, the blue arrows represent the HTTPS redirect from DigitalDownload to the Co-Branded UI, and the corresponding response from the Co-Branded service.
The gold arrows represent the request from DigitalDownload to the Amazon FPS API to process the payment, and the corresponding response.
The ID that identifies the buyer's authorization of the payment is called the sender token.
A buyer who is ready to authorize a purchase clicks the Buy Now button to authorize the payment. The button redirects the buyer to the Co-Branded User Interface (CBUI).
The CBUI's authorization pipeline asks the buyer to sign in, specify a personal payment instrument (like a credit card), and authorize the purchase.
To make for a better buying experience, DigitalDownload uses the co-branding feature of the Co-Branding service to include their branding on the CBUI payment authorization web pages. The Buy Now button powered by Amazon FPS redirects buyers away from the DigitalDownload web site to Amazon's. But because of the co-branding on Amazon's CBUI web pages, buyers don't feel as if they've completely left the DigitalDownload web site. The CBUI provides continuity between the checkout and payment authorization experience.
The Co-Branded service returns the buyer to the DigitalDownload site. In the return URL, the service passes the sender token, which represents the buyer's authorization of the payment.
DigitalDownload then sends a
Pay request to the Amazon FPS API and includes
the sender token in the request. The response is an XML document containing the status of the
request. If the request succeeds, DigitalDownload lets the buyer download the music.