What is overage billing?

• An allowance. The amount the plan includes per period.
• An overage price. What one unit beyond the allowance costs, if it can be bought at all.
• A policy. What happens at the line: allow and charge, block, or prompt an upgrade.
• When it is paid. Taken from a prepaid balance as it happens, or added to a later invoice.

Usage-based billing

Charging for all use. Overage billing charges just for the use beyond what the plan includes.

Hard and soft limits

A hard limit refuses at the allowance; a soft limit lets use go on past it, often with overage charges.

Prepaid credits

Paying for usage in advance; overage can be taken from a credit balance instead of billed later.

• A policy per feature. Some features should stop at the limit; others should keep going and charge.
• Prices that stay put for existing customers. Customers pay the overage price of the plan they bought, not one changed later.
• Two requests at the line. Both can see one unit left; decide whether to hold the amount before the work.
• Usage that cannot be paid. Decide what happens when overage cannot be charged, and whether it stops further use.
• Telling the customer. Show how close they are to the limit before they cross it.

Overage sits in entitlements in ShipRev. Each capability carries one of three overage policies: allow and bill, block, or prompt to upgrade. Where overage has a price and the customer organization's prepaid wallet balance covers it, it is paid from that wallet as usage is reported; overage the wallet cannot pay is left unpaid and is not charged later. Each plan version keeps the overage price it was published with. Where the last unit must not go to two requests, you reserve the amount before the work and confirm it after.