Kill Bill is an open-source programmable platform that enables you to build custom billing solutions. That’s a mouthful, to say the least, but think of it as building blocks to implement your own billing workflows.
Similar to the Unix philosophy of composability over monolithic design, Kill Bill provides APIs to create various pricing models, manage subscriptions, generate invoices, integrate with various payment gateways, etc. Whether you are selling access to a digital service for $10 a month or selling a multi-tier cell-phone data plan, Kill Bill provides the primitives to do it so you don’t have to start from scratch.