PayPal APIs: Up and Running (O'Reilly)
Thursday, 28 April 2011

If your web application's success depends on how quickly and easily users can make transactions, then PayPal is a solution you can't afford to overlook. This Developer's Guide helps you determine which PayPal option is best for your situation, and provides step-by-step instructions with sample code written primarily in PHP and Objective-C.

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