The PayPal Name-Value Pair API (NVP API) enables you to leverage the functionality of the PayPal API by simply sending an HTTP request to PayPal and specifying request parameters using name-value pairs. The NVP API is a lightweight alternative to the PayPal SOAP API (i.e., SOAP module is not required) and provides access to the same set of functionality as the SOAP API.

You can use either HTTP Post or Get protocol to send payment information to PayPal, for example:

https://secure.myecommercesite.com/payment.php?USER=someone@unknowncompany.com&PWD=mypassword
&METHOD=GetExpressCheckoutDetails&TOKEN=EC-23T233ZP3DFB

With the NVP API, you can:

• Accept payments using Website Payments Pro.
• Search your transaction history and query details on past transactions.
• Automate back office functionality, such as capturing authorizations and processing refund

1, Download SDK (Java, .Net, PHP) from https://www.paypal.com/IntegrationCenter/ic_nvp.html, and development guide from https://www.paypal.com/en_US/pdf/PP_NVPAPI_DeveloperGuide.pdf

2, If you want to use PHP version, download it from here: https://www.paypal.com/IntegrationCenter/sdk/PayPal_PHP_NVP_Samples.zip

3, Extract code to a directory on your ecommerce web site, open index.html and run test page.

4, Open a Business Website Payments Pro account with PayPal, get your PayPal API Credentials.

5, Edit configuration file constants.php, replace the following lines with your API credentials:

define('API_USERNAME', 'sdk-three_api1.sdk.com');
define('API_PASSWORD', 'QFZCWN5HZM8VBG7Q');
define('API_SIGNATURE', 'A.d9eRKfd1yVkRrtmMfCFLTqa6M9AyodL0SJkhYztxUi8W9pCXF6.4NI');

if you want to go live with your code, change the following line from

define('PAYPAL_URL', 'https://www.sandbox.paypal.com/webscr&cmd=_express-checkout&token=');

to

https://www.paypal.com/webscr&cmd=_express-checkout&token=

If you get 10002 error message, i.e.,

Error Number :10002
Short : Security error
Long : Security header is not valid

it is most likely you were using a wrong Paypal server for API_ENDPOINT (in constants.php file). Here is a list of servers you should use:

For HTTPS protocol:

API Servers for API Signature Security
If you use an API signature, post the request to one of these servers:
Sandbox: https://api-3t.sandbox.paypal.com/nvp
Live: https://api-3t.paypal.com/nvp

API Servers for API Certificate Security
If you use an API certificate, post the request to one of these servers:
Sandbox: https://api.sandbox.paypal.com/nvp
Live: https://api.paypal.com/nvp

To add shipping address, you need to include the following shipping information in both DoDirectPayment.php and DoDirectPaymentReceipt.php files:

SHIPTONAME
SHIPTOSTREET
SHIPTOSTREET2
SHIPTOCITY
SHIPTOCOUNTRYCODE
SHIPTOPHONENUM
SHIPTOZIP

So the URL posted to the PayPal server will be like this:

requiredSecurityParameters]&METHOD=DoDirectPayment&CREDITCARDTYPE=VISA
&ACCT=4683075410516684&EXPDATE=012007&CVV2=808&AMT=212.95
&FIRSTNAME=Designer&LASTNAME=Fotos&IPADDRESS=255.55.167.002
&STREET=1234+Easy+Street&CITY=San+Jose&STATE=CA&COUNTRY=United+States
&ZIP=95110&COUNTRYCODE=US&PAYMENTACTION=Sale
&SHIPTONAME=Louise+P.+Flowerchild&SHIPTOSTREET=1234+Easy+Street
&SHIPTOSTREET2=Apt+22+bis&SHIPTOCITY=New+Orleans&SHIPTOSTATE=LA
&SHIPTOCOUNTRYCODE=US&SHIPTOPHONENUM=504-555-1212&SHIPTOZIP=70114

With Website Payments Pro, you get the payment processing capabilities of a merchant account and gateway plus much more. It is an all-in-one payment solution that includes PayPal Direct Payment API and PayPal Express Checkout.

• Direct Payment API enables you to accept credit card payments directly on your website. PayPal remains invisible, so you control the customer experience.
• PayPal Express Checkout allows PayPal account holders to check out fast with saved account information, and enables you to gain incremental sales from PayPal’s growing base of users (over 71 million users).
• Optionally, you can accept payments for phone, fax, and mail orders. Website Payments Pro includes Virtual Terminal, which allows you to conveniently process payments for these types of transactions and increase revenue.

1, Install PHP5.

2, Install essential PHP extension:

yum install php-soap
yum install php-pear
yum install php-xmlrpc
apachectl restart

3, Download phpPaypalPro from https://sourceforge.net/project/showfiles.php?group_id=187933

4, Extract phpPaypalPro to your ecommerce web site. Test examples.php to see if the package works.

5, Sign up with PayPal for a (business) Website Payments Pro account, get your PayPal API Credentials (

Google: https://www.google.com/webmasters/tools/siteoverview

Yahoo: https://siteexplorer.search.yahoo.com/submit

MSN: http://search.msn.com.my/docs/submit.aspx?FORM=WSSM