Now that our billing engine is enabled on every organizations, we can consider implementing more flexible features around billing cycles. In particular, we want to add more flexibility to recurring intervals. Currently, we only support monthly and yearly.

Proposal

Similar to what we did for trials, we propose to configure the recurring interval using two properties:

• An interval: day, week, month, year
• An interval count: the number determining the length of the cycle. For example 2 month would mean the subscription would be billed every two months, 14 days, every 14 days, etc.

Backend tasks

• Add the necessary properties to the Product and Subscription models
• Create the database migration to add those fields and migrate existing Products and Subscriptions
• Expose and handle those properties correctly in the Product, Subscription and Checkout API
• Handle the configuration correctly when handling a cycle. Tip: SubscriptionRecurringInterval.get_next_periodalready has most of the logic necessary.

Frontend tasks

• Adapt the Product creation/update form to configure the recurring interval
  • Nice to have: show quick and common configurations by default like 1 month or 1 year
• Display the interval nicely across the dashboard (Product details, Subscription details…)
• Display the interval nicely in the Customer Portal
• Display the interval nicely in the Checkout form
  • A bit more touchy since this requires to generate the public JS SDK (https://github.com/polarsource/polar-js) with the latest API changes. Feel free to reach out for guidance.