The Billing and Monetization Glossary

A billing cycle is the recurring period a subscription invoice covers, running from an anchor date to the day before the next anchor date. The cycle sets which charges land on which invoice and which period any proration, usage rollup, or plan change gets applied to.

A billing engine is the component of a billing system that turns metered usage, contract terms, and pricing rules into invoice line items. The engine handles rating, proration, discounts, credits, and tax application, then hands a finalized invoice to a payment provider for collection.

Billing frequency is how often a customer receives an invoice, chosen from options like weekly, monthly, quarterly, or annual. The choice sets when cash arrives, how large each invoice is, and how often a customer faces a renewal decision, independent of how often usage gets measured.

Billing in advance means charging a customer at the start of the period the charge covers, before you deliver the service. Fixed fees and prepaid credits bill this way because you know their quantity up front, while metered usage can't, since the consumed amount doesn't exist yet.

Billing in arrears is a billing model where a company invoices a customer after the service period ends, once the quantity consumed is known. Usage-based and metered products bill this way by necessity, because the amount owed doesn't exist until the period closes.

A billing period is the span of time that a single invoice covers. It sets the boundaries for every charge on that invoice: which usage events count toward it, which subscription fees apply, and which date the billing system uses to close the books and generate the document.

Billing vs invoicing describes the difference between calculating what a customer owes and issuing the document that demands payment. Billing is the whole process: metering, pricing, applying credits, and producing a total. Invoicing is one step inside it, the point where that total becomes a legal document.