Download PayPal Express Checkout - 2012 Integration Guide

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PayPal Name-Value Pair API
Basics
The Name-Value Pair (NVP) API provides parameter-based association between request and
response fields of a message and their values. The request message is sent from your website
by the API, and a response message is returned by PayPal using a client-server model in which
your site is a client of the PayPal server.
NOT E :
The PayFlow API also uses name-value pairs to provide parameter-based association
between request and response fields of a message and their values; however, the
PayFlow API is not the same as the NVP API; for more information about the
PayFlow API, see Gateway Developer Guide and Reference.
PayPal API Client-Server Architecture
The PayPal API uses a client-server model in which your website is a client of the PayPal
server.
A page on your website initiates an action on a PayPal API server by sending a request to the
server. The PayPal server responds with a confirmation that the requested action was taken or
indicates that an error occurred. The response might also contain additional information
related to the request. The following diagram shows the basic request-response mechanism.
For example, you might want to obtain the buyer’s shipping address from PayPal. You can
initiate a request specifying an API operation to obtain buyer details. The response from the
PayPal API server contains information about whether the request was successful. If the
operation succeeds, the response contains the requested information. In this case, the response
contains the buyer’s shipping address. If the operation fails, the response contains one or more
error messages.
Related information:
"Creating an NVP Request" on page 58
"Responding to an NVP Response" on page 62
Express Checkout Integration Guide
August 7, 2012
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