Per-seat Billing for Subscriptions

If your subscription plans are quantity-enabled, you can implement per-seat billing to allow customers to purchase seats.

To implement per-seat billing for buying seats for additional team members, you can use the Update Users API and amend the quantity parameter to the required number of seats.

We would recommend setting both the bill_immediately and prorate parameters to true. This will calculate the differential price for the change in seats for the remainder of the current billing period, and charge the buyer for the difference at the point that the subscription is amended. To instead charge the buyer the prorated difference at the start of the next billing period, simply set bill_immediately to false - the prorated charge will be added on top of the buyer’s scheduled payment amount.

curl -X POST -d 'vendor_id=123' \
             -d 'vendor_auth_code=1a54229abfcfa...' \
             -d 'subscription_id=12345' \
             -d 'quantity=7' \
             -d 'bill_immediately=true' \
             -d 'prorate=true' \
https://vendors.paddle.com/api/2.0/subscription/users/update

The Subscription Updated and Subscription Payment Succeeded alerts can be used to monitor that update payments have completed successfully.