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"Metered Usage" with upfront payment (credits/points)

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dominik

26 Feb, 2013 11:16 PM

Hi,

how would I implement a credit based system like postmark does?
What I want basically is something like this:

• Users can purchase (packets of) credits
• Using feature X costs one credit per usage
• Once all credits are used up - access to feature X is denied
• Users can stock up credits any time - credits don't expire
• Users can set up auto-renewal of credits, e.g. when credits are < 10% of last credits purchase, a credit-package is automatically purchased

is that possible?
Thanks!

1. Support Staff 1 Posted by Marc Guyer on 27 Feb, 2013 12:53 PM

   

   Hi Dominik - You can do that with tracked items. The standard way to do it is to track the amount of usage over the billing period and then charge for the amount used at the end of the period. You can do it in reverse, too. The technique isn't documented so I'll describe it here:

   • Name: Prepaid Credits
   • Quantity Included: 99999999.9 -- Unlimited. Yes, this is confusing. What this indicates in the case of prepaid credits is that you can prepay for an unlimited number of credits (as far as CheddarGetter is concerned).
   • Overage Amount: 0 -- There's no such thing as overage with prepaid credits. You could, however, set this to the amount you charge per credit so you can make it different on each plan and use CG's config as the authority on what you charge on each plan.
   • Monthly: No -- The current quantity allocated to the customer is carried over to the next billing cycle. If set to Yes, the quantity is reset to zero at the beginning of each billing cycle.

   So, that's the pricing plan config for prepaid credits. The other piece is the act of prepayment and recording the amount currently allocated. Use a one-time invoice to charge for a block of credits. The charge uses the customer's payment method on file so it can be a "one click" buying experience. You could even make it automatic. Upon a successful charge for more credits, use the CG API to add the amount purchased to the customer's current quantity of the item.

   The key API calls are:

   • invoices/new - https://cheddargetter.com/developers#one-time-invoice - Transact a one-time invoice for any amount of credits for any price. You could use the pricing plan item over amount config to determine the cost of each credit.
   • customers/add-item-quantity - https://cheddargetter.com/developers#add-item-quantity - Upon a successful prepayment, update the customer's quantity.
   • customers/new - https://cheddargetter.com/developers#add-customer - You can also charge for and record initial quantity on new customer creation.

   Let us know if you have questions.

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2. Jess Pendley closed this discussion on 21 Nov, 2013 07:35 PM.