If you are using Composer you can get going quickly through our Packagist repo.  If you are not using Composer you can simply download the class library and add it to your project.  If you would like more details on either of these mothods take a look at our install guide.

PayPal PHP SDK Class Library Install Guide

• Open the template file that corresponds to the API call you’d like to make.
  • Example: If we want to make a call to the RefundTransaction API we open /templates/RefundTransaction.php
• You may leave the file here or save this file to the location on your web server where you’d like this call to be made.
  • I like to save the files to a separate location and keep the ones included with the library as empty templates.
  • When working within an MVC framework, it’s a good idea to copy/paste the template functionality into a Model method.
• Each template file includes PHP arrays for every parameter available to that particular API. Simply fill in the array parameters with your own dynamic (or static) data. This data may come from…
  • Session Variables
  • PHP Variables
  • Database Recordsets
  • Static Values
  • Etc.
• When you run the file you will get a $PayPalResult array that consists of all the response parameters from PayPal, original request parameters sent to PayPal, and raw request/response info for troubleshooting.
  • You may refer to the PayPal API Reference Guide for details about what response parameters you can expect to get back from any successful API request.
    • Example: When working with RefundTransaction, I can see that PayPal will return a REFUNDTRANSACTIONID, FEEREFUNDAMT, etc. As such, I know that those values will be included in $PayPalResult[‘REFUNDTRANSACTIONID’] and $PayPalResult[‘FEEREFUNDAMT’] respectively.
• If errors occur they will be available in $PayPalResult[‘ERRORS’].

• The result of the API call will come back in $PayPalResult[‘ACK’].
  • Remember when checking the value that it could be Success, Failure, SuccessWithWarning, or FailureWithWarning. Simply checking for Success isn’t enough.
  • You may use $PayPal->APICallSuccessful($Ack) to do this for you.

• Create an account at http://developer.paypal.com
• Create at least one sandbox Seller account and one sandbox Buyer account from within your developer account.
  • These accounts can be used to go through the entire process of buying items within your application, and reviewing what each party involved will see in their PayPal account when the transaction is completed.

• Review PayPal’s Going Live Information
• Move /includes/config.php to a directory outside your web root.
  • When you do this you’ll need to make sure any scripts where the config is included are updated to use the system path instead of the site path.