Integration Guide

Table Of Contents
PayPal Name-Value Pair API Basics
Executing NVP API Operations
3
34 May 2010 Express Checkout Integration Guide
List Syntax for Name-Value Pairs
The PayPal API uses a special syntax for NVP fields defined as lists.
The NVP interface to the PayPal API requires a unique name for each field. In the API, lists
are prefixed by L_. To identify an element within the list, use the offset from the beginning of
the list, starting with 0 as the first element. For example, L_DESC0 is the first line of a
description, L_DESC1, is the second line, and so on.
NOTE: Not all lists follow the L_ prefix convention; however, all lists start with 0 as the first
element.
Executing NVP API Operations
You execute an PayPal NVP API operation by submitting an HTTP POST request to a PayPal
API server.
Specifying a PayPal Server
You execute a PayPal API operation by submitting the request to a PayPal API server.
To execute a PayPal NVP API operation, submit your complete request to one of the following
end points:
NOTE: You must use different API credentials for each server end point. Typically, you
obtain API credentials when you test in the Sandbox and then obtain another set of
credentials for the production server. You must change each API request to use the
new credentials when you go live.
Logging API Operations
You should log basic information about each PayPal API operation you execute.
Server end point Description
https://api-
3t.sandbox.paypal.com/nvp
Sandbox server for use with API signatures; use for testing your
API
https://api-3t.paypal.com/nvp PayPal “live” production server for use with API signatures
https://api.sandbox.paypal.com/nvp Sandbox server for use with API certificates; use for testing
your API
https://api.paypal.com/nvp PayPal “live” production server for use with API certificates