Integration Guide

Table Of Contents
Express Checkout Integration Guide October 2009 25
3
PayPal Name-Value Pair API
Basics
The PayPal API uses a client-server model in which your site is a client of the PayPal server.
z PayPal API Client-Server Architecture
z Obtaining API Credentials
z Creating an NVP Request
z Executing NVP API Operations
z Responding to an NVP Response
PayPal API Client-Server Architecture
The PayPal API uses a client-server model in which your site is a client of the PayPal server.
You set up web pages on your site that initiate actions 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 that an error occurred. The response may contain additional information related
to the request. The following diagram shows the basic request-response mechanism.
For example, you might want to obtain the customers shipping address from PayPal. You
could initiate a request that specifies an API operation that gets customer details. The response
from the PayPal API server would contain information about whether the request was
successful. If the operation was successful, the response would contain the requested
information; in this case, the customers shipping address. If the operation fails, there will be
one or more error messages.
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, a request is generated on your site. At the PayPal server, the request
is executed, and the response is returned to your site.