I have few questions regarding PayPal subscriptions and IPN.
According to this answer, when using PayPal recurring payments (subscriptions), PayPal sends two types of notifications when a subscription is made:
a) An IPN with txn_type of subscr_signup is sent once
b) An IPN with txt_type of subscr_payment is a recurring IPN that is sent every time a subscription payment is made.
So I have the following questions
Is the custom field sent for every subscr_payment made? And does it have the same value always?
What is subscr_id? Is it subscriber ID or subscription ID? I am assuming it is the subscriber ID, and therefore, I am also assuming that it will be the same per subscriber if he/she has more than one subscription in the site (assuming the site offers more than one item available for subscription). Is my assumption correct?
Is txt_id different for every new transaction? In other words, when two consecutive payments are made for the same subscription, are they going to have different txt_id's?
What is the id field in subscr_payment?
Is there a field that is sent with the subscr_payment message which allows us to identify which subscription is being renewed? I am thinking this is a subscription ID that will have the same value for all payments made to that subscription. Again, the reason I ask is my site is offering more than one subscription per user. And I need a way to identify which subscription is being renewed when an IPN message is sent.
1) No, it will not be included in the payment IPNs.
2) It's basically the same thing. Their documentation calls it a "subscriber ID" but it's treated as a subscription profile ID.
3) You must mean txn_id..?? Yes, each individual payment for a profile would have its own txn_id. I'm a little confused how you would two consecutive payments, though..?? It would be per week, per month, or whatever the profile is setup as.
4) Need a sample of what you're referring to here.
5) Again, this would be the subscr_id.