Billing, in plain terms.

The autonomous system that watches every account's balances, usage and payments, and runs playbooks — top-ups, recovery, expansion, churn alerts — on autopilot, approve-first, or alert-only.

A secret credential used to authenticate requests. Test keys write to a sandboxed ledger; live keys bill real money, and the two never mix.

The unpleasant surprise of an invoice far larger than expected, usually from unmonitored usage growth. Prevented with spend alerts before the invoice, not after.

The rate at which usage depletes a prepaid credit wallet. Mapping events to credit costs determines how fast a balance burns down.

A customer canceling or not renewing. In usage-based pricing, a usage drop is an early churn signal — if it isn't just seasonality.

A minimum spend or volume a customer agrees to for a period, typically at a discount, with overage billed beyond it.

A prepaid balance that usage burns down over time. Wallets can hold paid credits, promotional grants, and trial credits separately.

The process of following up on a failed or overdue payment — retries and reminder emails aimed at recovering revenue without alienating the customer.

Whether a customer is allowed to use a feature right now, based on their plan, seats and live credit balance — checked with a single API call.

A single record of product usage — an API call, a token, a compute-second — sent to the billing system and aggregated into totals.

Free credits issued to a wallet, with an expiry — used for trials, make-goods or launch promos. Grants burn before paid credits.

A unique identifier attached to an event so a duplicate delivery — from a retry, for example — is recognized and ignored rather than double-counted.

A billing document assembled from subscription, usage and credit line items for a period, then sent for collection.

The append-only, immutable record of every usage event. Totals and invoices are derived views computed from the ledger, not mutated counters.

The practice of measuring product usage in real time so it can be priced and billed accurately.

The predictable subscription revenue a business collects each month, excluding one-time and highly variable usage charges.

Usage beyond an included allowance or commitment, billed at a separate — often higher — rate.

A predefined automated response to a billing signal — wallet top-ups, payment recovery, expansion offers, churn outreach, bill-shock alerts, or commit tracking.

The self-serve surface where customers manage checkout, plans, payment methods and invoice history — hosted or embedded, branded to the seller.

A controlled test of a price, tier or bundle change against a cohort of customers, measured against a control group before a full rollout.

Adjusting a charge for a partial period — for example, when a customer upgrades mid-cycle and only owes for the days remaining.

Winning back revenue from a failed charge through a retry, an updated payment method, or a dunning message matched to the decline reason.

Charging per named user or license, often combined with usage-based pricing in hybrid plans.

A pricing structure where the rate changes at defined volume thresholds — for example, a lower per-unit rate after the first 10,000 units.

Adding funds to a depleted credit wallet, either through a one-click link, an auto-charge the customer opted into, or a manual payment.

Charging customers based on how much of a product they actually consume, rather than a flat recurring fee.

An HTTP callback that notifies an external system the moment something happens — an invoice is issued, a payment fails, the agent takes an action.