The team here at Chargify has been hard at work on a bunch of new features. We just flipped the switch on two of these: Prorated Upgrades/Downgrades and Metered Components.
Metered Components give Sellers the ability to charge for a product on a per-usage basis. For example, a cell phone provider could charge $1 for each text message that was sent, or a Web Hosting company could charge for storage by the number of gigabytes used. Creating metered components is quick and easy. Simply give the component a name, specify the unit used to measure it, and give it a per unit price. Usage of metered components is tallied throughout the billing cycle and the charge is seamlessly integrated as a line item on the Customer’s next invoice.
We also just launched Prorated Upgrades and Downgrades. As a Seller, you can now migrate a Customer from one Product to the next and Chargify will handle the pricing differences for you. For example, if I move a Customer from a Basic to a Premium plan, a credit for the remainder of a the current plan will be created and the Customer will be charged for the new Premium subscription. Migrations can be initiated both through the Admin Interface as well as the API.