2009

Table Of Contents
Name-Value Pair API Developer Guide 08 April 2009 17
PayPal NVP API Overview
Technical Details
Response Format
A response from the PayPal servers is a URL-encoded name-value pair string, just like the
request, except it has the following general format.
General Format of a Successful Response
Each response includes the ACK field. If the ACK field’s value is Success or
SuccessWithWarning, you should process the API response fields. In a successful response,
you can ignore all fields up to and including the BUILD field. The important fields begin after
the BUILD field.
Error Responses
If the ACK value is Error or Warning, API response fields are not returned. An error response
has the following general format.
Format of an Error Response
For possible causes of errors and how to correct them, see the explanation of the specific error
code, short message, and long message in “API Error Codes” on page 159.
ACK Parameter Values
The following table lists values for the ACK parameter.
ACK Parameter Values
Success Response Fields ACK=Success&TIMESTAMP=date/timeOfResponse
&CORRELATIONID=debuggingToken&VERSION=...
&BUILD=buildNumber
API Response Fields &NAME1=value1&NAME2=value2&NAME3=value3&...
Response Fields on
Error
ACK=Error&TIMESTAMP=date/timeOfResponse&
CORRELATIONID=debuggingToken&VERSION=VersionNo&
BUILD=buildNumber&L_ERRORCODE0=errorCode&
L_SHORTMESSAGE0=shortMessage&
L_LONGMESSAGE0=longMessage&
L_SEVERITYCODE0=severityCode
Multiple errors can be
returned. Each set of
errors has a different
numeric suffix, starting
with 0 and incremented
by one for each error.
Type of Response Value
Successful response Success
SuccessWithWarning
Error response Failure
FailureWithWarning
Warning