title: good php-based toolkit or backend software for paypal subscription management?
body: <p>Does anyone know of a good "toolkit", set of pre-built classes, or otherwise some type of php software that can help manage subscriptions/recurringpayments for paypal?  This would be for a web-based service that users subscribe to and pay monthly.  </p>
  
  <p>Open source is preferable and really I'm looking for something that can be edited or customized from the server side as needed.  </p>
  
  <p>Thanks</p>