2012

PayPal Name-Value Pair API Basics
PayPal API Client-Server Architecture
1
16 August 2012 Name-Value Pair API Developer Guide
PayPal Name-Value Pair API Requests and Responses
To perform a PayPal NVP API operation, you send an NVP-formatted request to a PayPal
NVP server and interpret the response.
In the following diagram, your website generates a request. The request is executed on a
PayPal server and the response is returned to your site.
The request identifies:
 The name of the API operation, specified by METHOD=name, to be performed and its
version
NOTE: After the METHOD parameter, you can specify the parameters in any order.
 Credentials that identify the PayPal account making the request
 Request-specific information that controls the API operation to be performed
A PayPal API server performs the operation and returns a response. The response contains:
 An acknowledgement status that indicates whether the operation was a success or failure
and whether any warning messages were returned
 Information that can be used by PayPal to track execution of the API operation
 Response-specific information required to fulfill the request
UTF-8 Character Encoding
The PayPal API assumes that all data in requests is in Unicode, specifically, the Unicode (or
UCS) Transformation Format, 8-bit encoding form (UTF-8).
In responses, the API always returns data in UTF-8.
Multiple API Operations
Some of the features, such as Express Checkout, require you to call multiple API operations.
Typically, these features require you to: