I have to integrate PayPal Standard Payments in my Saas for a monthly subscription.
I found a few tips in the PayPal documentation about using API but it's not my case.
If after a few months a payment fails because the client has no money, does it automatically retry to charge the client in the next days or should I set a custom field?
There is a variable sra when set to 1 , PaYPal will try to collect the payment two more times before canceling the subscription. More information on Recurring Payments Reattempts
How PayPal Reattempts Failed Recurring Payments
PayPal reattempts to collect recurring payments three days after the day on which recurring payments fail. If the first reattempt to collect a recurring payment fails, PayPal waits 5 days to reattempt a second time. If the second reattempt fails, PayPal cancels the subscription.
来源：https://stackoverflow.com/questions/26546558/does-paypal-standard-automatically-retry-to-charge-the-client-if-a-payment-fails