title: How to interprete paypal billing agreement creation?
body: <p>I am building a paypal subscription system but i have some difficulties to understand some points. When using sandbox i can't simulate a payment denial process so when the payment is made, paypal redirect me to my "approval url callback" and a billing agreement is created. </p>
  
  <p>So i want to know , in a real situation, will paypal redirect me to the approval url and create this billing agreement even if the payment didn't occur yet ? or this one can be created if and only if the payment is accepted ? (So if paypal denied the payment the billing agreement will never be created)</p>
  
  <p>In my case, my customers will need to access to some paid features of my website so, should i wait for the "ipn webhook notification (PAYMENT.SALE.COMPLETED)" which can take several minutes to be fired to my endpoint, or can i grant access immediately after the billing agreement is created ?</p>
  
  <p>Which is the most secure thing to do ?</p>
  
  <p>thanks.</p>