Integration Guide
Table Of Contents
- Express Checkout Integration Guide
- Contents
- Preface
- Introducing Express Checkout
- Express Checkout Button and Logo Image Integration
- PayPal Name-Value Pair API Basics
- Implementing the Simplest Express Checkout Integration
- Testing an Express Checkout Integration
- Customizing Express Checkout
- Implementing the Instant Update API
- Immediate Payment
- Implementing Parallel Payments
- Handling Payment Settlements
- Handling Recurring Payments
- How Recurring Payments Work
- Recurring Payments Terms
- Options for Creating a Recurring Payments Profile
- Recurring Payments With Express Checkout
- Recurring Payments Profile Status
- Getting Recurring Payments Profile Information
- Modifying a Recurring Payments Profile
- Billing the Outstanding Amount of a Profile
- Recurring Payments Notifications
- Using Other PayPal API Operations
- Integrating giropay with Express Checkout
Express Checkout Integration Guide May 2010 35
PayPal Name-Value Pair API Basics
Responding to an NVP Response
3
All responses to PayPal API operations contain information that may be useful for debugging
purposes. You should log the Correlation ID, which identifies the API operation to PayPal,
and response-specific information, such as the transaction ID, which you can use to review a
transaction on the PayPal website or through the API. You can log other information that may
be useful, such as the timestamp. You could implement a scheme that logs the entire request
and response in a “verbose” mode; however, you should never log the password from a
request.
Responding to an NVP Response
The Name-Value Pair response consists of the answer to the request as well as common fields
that identify the API operation and how it was executed.
The following diagram shows fields in the response to a PayPal NVP API operation:
Common Response Fields
The PayPal API always returns common fields in addition to fields that are specific to the
requested PayPal API operation.
A PayPal API response includes the following fields:
Field Description
ACK Acknowledgement status, which is one of the following values:
z Success indicates a successful operation.
z SuccessWithWarning indicates a successful operation; however, there are
messages returned in the response that you should examine.
z Failure indicates the operation failed; the response also contains one or more error
messages explaining the failure.
z FailureWithWarning indicates that the operation failed and that there are
messages returned in the response that you should examine
CORRELATIONID Correlation ID, which uniquely identifies the transaction to PayPal
TIMESTAMP The date and time that the requested API operation was performed
VERSION The version of the API
BUILD The sub-version of the API