I'm wondering if it's possible to use Paypal Adaptive Payments in the way that Kickstarter.com are using Amazon Payments to collect/fundraise.
For example: A user sets up a project. People pledge $5 to that project, and if it meets a goal, the system then automatically extracts the money from everyone, and puts it into user who created the projects paypal account. Is this possible using Paypal?
Are there any good PHP libraries supporting Adaptive Payments, if this is possible?
I was also looking for the same answer since I am working on a similar crowdfunding platform as Kickstarter is, but I need to use PayPal.
After a lot of Googling and reading about PayPal's Adaptive Payments API I found out that it's possible by using the Preapproval API and then if the project is funded I can use Chained Payments to send the money to the project creator and to also retain a small fee (a percentage) for using the crowdfunding platform.
If you are looking for some PHP libraries you can found 2 versions at the links below. One is a library for the CodeIgniter framework and the other one is a PHP API class that can be used anywhere. So, here are the links:
CodeIgniter Library - http://www.binpress.com/app/paypal-adaptive-payments-pro-codeigniter-library/140
PHP API Class - http://www.binpress.com/app/php-paypal-pro-adaptive-api-class/612
I see now that your question is 2 years old, I just hope this answer helps others looking for answers regarding PayPal's Adaptive Payments API.
Yes, it is possible using the Adaptive Payments Preapproval API. When someone 'pledges' would be when you set up the preapproval, and then you can run that preapproved transaction at some future time without any additional interaction required.
PayPal has developed a PHP SDK with libraries and examples to get you started.
This answer is a couple of years late but better late than never! The one downside to using the Adaptive Payments Preapproval API for a Kickstarter type of system is that you can't guarantee the "pledge" will be valid when you go to make the withdrawal, since it is possible for the user to cancel their pledge at any time.
I've been working on a crowdfunding project similar to kickstarter. I started out using paypal's adaptive payments for this kind of thing but I eventually switched to wepay's preapproval api. I'm glad I did. For one thing, their documentation is clearer and better organized with good examples in PHP, Ruby and Python.
