For more current information, see https://rsvpmaker.com/blog/category/paypal/
RSVPMaker includes integration routines from the PayPal software developer’s kit to allow you to solicit online payments for your events and record which users have paid. The setup is a little bit involved, but there’s a reason for it.
I could have made it easier to set up RSVPMaker to work with PayPal, but for security reasons I hesitated to do so. If I had you enter your security credentials into a WordPress and save them as options associated with the application, they would be stored in the WordPress database and potentially be vulnerable to exposure through any hack that might allow someone to gain database access. While WordPress is secure enough for many purposes, it does get hacked from time to time, and I wouldn’t want anyone to gain access to your PayPal account (and, indirectly, to your bank and credit card accounts) for the sake of making things more convenient.
So I instead require you to edit the paypal_constants.php file in the paypal subdirectory of the RSVPMaker distribution. You will have to enter your API Username, API Password, and API Signature in that file. To obtain these you must have a Business or Premier PayPal Website Payments Standard or Website Payments Pro account (in most cases, I recommend Website Payments standard, which provides the needed functionality but does not require a monthly fee). Log into PayPal and visit the Profile Menu, follow the link to API Access, and then View API Signature. This will display the codes you need to copy into the configuration file.
I recommend storing this file outside of the web root directory — or at least somewhere other than the default location — so that it’s not possible for an attacker (who may have read these instructions) to browse to
and make some kind of mischief on it. If your directory structure is /home/account/public_html then putting the file in /home/account and giving it a different name would be better.
Once you have this set up, record the path to the configuration file on the Settings screen for RSVPMaker, and you should be good to go.
Create a test event with a fee associated with it, go through the RSVP process, and you should be prompted to pay online. When you click the Pay Now button, you should be redirected to a page on the PayPal website that displays the name of your organization and asks you to either log in or provide credit card information to make a purchase.
Here is a visual walkthrough of the setup steps: