I am working on using PayPal’s API for TransactionSearch – https://cms.paypal.com/us/cgi-bin/?cmd=_render-content&content_ID=developer/e_howto_api_nvp_r_TransactionSearch. The sample php code is at https://cms.paypal.com/cms_content/US/en_US/files/developer/nvp_TransactionSearch_php.txt
I have a PayPal business account, and I have created an API username, password and signature. Using the same PayPal account, I granted access to my API username so that I could begin testing. Using PHP and (cURL), I have successfully sent and received information via the API. All works fine.
The goal is that I will provide my API username to multiple end users, so that my application can query their PayPal information, and import their historical records into the application for the users to view. The part that I dont get: using the TransactionSearch API, I dont see anywhere to specify a PayPal Email address – i.e. the PayPal account that I am going to query for historical information. How or where do I query multiple individual PayPal accounts?
It seems that there is an additional API parameter that can be used called SUBJECT
SUBJECT
Optional
Email address of a PayPal account that has granted you permission to make this call.
Set this parameter only if you are calling an API on a different user’s behalf.
https://www.paypalobjects.com/en_US/ebook/PP_NVPAPI_DeveloperGuide/overview.html#2076088