Sending a Co-Branded Service Request

This section shows how to send a request that redirects the buyer to the CBUI. You must send a Co-Branded service request before you can use an Amazon FPS Pay or Reserve request.

These requests are typically implemented as an HTML form on your web site. Your site dynamically updates the values of the Co-Branded service request parameters according to the items purchased.

To send a Co-Branded service request

Add up all the charges for all of the items the buyer wants to purchase, together with all taxes, shipping fees, and any additional fees (such as gift wrapping fees).
Use the Single Payment Co-Branded API as well as the parameters common to all Co-Branded service requests to construct a request similar to the following example. For information about the Single Payment Co-Branded API, see Single-Use Token API. For a list of the parameters common to all Co-Branded service requests, see Common Parameters.
This example request is for a one-time payment (SingleUse) for the download of an Elton John song.
```
https://authorize.payments.amazon.com/cobranded-ui/actions/start?
callerKey=[The caller's AWS Access Key ID]
&callerReference=DigitalDownload1183401134541
&pipelineName=SingleUse
&returnURL=http%3A%2F%2Fwww.digitaldownload.com%2FpaymentDetails.jsp%3FPaymentAmount%3
D0.10%26Download%3DCandle%2BIn%2Bthe%2BWind%2B-%2BElton%2BJohn%26uniqueId%3D1183401134535
&paymentReason=To download Candle In the Wind - Elton John
&signature=[URL-encoded value you generate]
&transactionAmount=0.10
```
The optional parameters vary in your request according to what the buyer purchases.
For information about getting your AWS Access Key ID value, go to the Amazon Flexible Payments Service Getting Started Guide.
Programmatically populate this request with the parameter values based on the items the buyer is purchasing.
Calculate the signature and include it in the request.
For more information about creating the value for signature, see Working with Signatures.
Implement the Pay Now button on your web site to send this request.

	Note
	We recommend that you first try your Co-Branded service request in the Amazon FPS Sandbox. For more information, see Testing Your Applications for Free.