Modify Subscriptions using PayPal vs Amazon FPS

Question

I have been looking at setting up web applications that rely heavily on the ability for users to frequently and substantially modify subscriptions. I may be using marketplace features as well, and I need a system that supports both seamlessly.

I have seen multiple horror stories about the complexity of modifying subscriptions, including double billing, or cutting users off at the wrong time.

I sincerely hope, for instance, that this article http://talklikeaduck.denhaven2.com/2007/09/02/how-to-cure-the-paypal-subscription-blues

is out of date. The use cases that I have in mind are even more complex than the ones that he mentioned. For a sampling of what I would like to do:

• Support multiple subscriptions and subscription types/levels. For instance one user might have 1 Plan A billed monthly at $10 and 10 plan C billed at $50 per month and 1 Plan D billed at $100 per year.
• Support changing of arbitrary payment amounts. For instance, user was on the $40 per month plan, but then changes that to a $100 per month plan. Then cancels, then signs up again at $50 per month before the $100 period was up. The user should still get $100 of service for the month that he paid $100 for, and then should change to the $40 per month plan.
• Allow for payments of subscription amounts between my users. So one user might initiate a payment of 50% of whatever amount he has paid into the system so far. My application will be handling these types of marketplace style operations and these payments should work in the context of subscriptions...

It does not appear that there is an Open Source PHP library that does what I need either with Amazon or Paypal. So I am looking forward to coding this myself. (be glad to be proved wrong here, perhaps a Freemium for PHP?). I cannot use the various subscription services that are available . Because they generally do not support the features above, and because I need to have direct access to the PayPal or Amazon FPS API for later cleverness via marketplace issues.

Which brings me to my question. Which payment platform should I choose for ease of managing subscriptions? Please send me in the right direction, I only have so much time. But I also do not have time to make the wrong decision. Please provide evidence for your preferences, and if possible detail your work comparing the two systems. Google has the only other payment platform and currently their subscription system is in beta.. If you propose some other better system, please provider tons of good reasons, because I need a popular payment engine that people will feel comfortable with!

-FT

Answer 1

I see you asked this question back in December... if you haven't found an answer yet, I have some suggestions based on my experience with a business problem almost identical to yours.

Which PayPal API are you thinking of using? In using the PayFlow XML API, I found it was thousands of times easier to just roll my own subscription service. If the API you're using supports creating 'reference transactions' based on the previous successful transaction ID, you may save yourself a headache by keeping track of users' subscription amounts, keeping track of what's been paid, and creating a billing script that runs on a daily cronjob, checking each user to see if they need to pay (and how much), and then creating a reference sale for each of them.

Of course, don't forget that you have to explicitly ask for users' permission before you start billing them on a recurring basis, and there should be a good recurring billing and privacy policy. One trouble with this setup is that you pretty much need to create your own scripts to manage people's subscriptions and payments -- fortunately, I was tacking PayPal recurring billing onto a web app that already had subscriptions and accounting built-in.

Let me know if you need any suggestions on how to go about this!