Glossary

Billing, in plain terms.

Every term you’ll run into building usage-based pricing — from wallets to webhooks — defined in one place.

A
AgentAutomation

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.

API keyAccess

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

B
Bill shockCustomer experience

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

Burn-downWallets

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

C
ChurnRevenue

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

Commit / CommitmentPricing

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

Credits / WalletWallets

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

D
DunningPayments

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

See also:Recovery
E
EntitlementAccess

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.

See also:API key
Event (usage event)Metering

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

G
Grant (credit grant)Wallets

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

I
Idempotency keyMetering

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

InvoicePayments

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

L
LedgerMetering

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

M
MeteringMetering

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

MRR (Monthly Recurring Revenue)Revenue

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

O
OveragePricing

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

P
PlaybookAutomation

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

See also:Agent
Portal (customer portal)Customer experience

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

Pricing experimentPricing

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

ProrationPricing

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

R
Recovery (payment recovery)Payments

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

See also:Dunning
S
Seat-based pricingPricing

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

T
Tier / Tiered pricingPricing

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

Top-upWallets

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

U
Usage-based pricingPricing

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

W
WebhookAccess

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

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