AI metering and billing glossary
Short, plain-English definitions for the terminology used in AI usage billing, AIPricingLab, and adjacent platforms.
Metered billing
Charging customers based on what they actually consumed in a billing period - tokens, image renders, agent runs - instead of a flat subscription fee.
TermUsage-based pricing
A pricing model where the customer's bill scales with their usage of the product, instead of a flat subscription. Sometimes called "consumption pricing" or "pay-as-you-go".
TermTokens
The unit of input and output for large language models - roughly 0.75 of a word in English. LLM providers price by tokens; metering AI apps usually does too.
TermQuota
A hard or soft cap on a usage unit (tokens, renders, seconds, cents) over a period (daily, monthly, lifetime). The "100 / month" in "100 image renders / month".
TermRate limit
A short-window cap on how often a request can be made - typically per-second or per-minute. Distinct from a quota, which is a long-window cap.
Termreserve / commit / release
The atomic three-step pattern that gates AI calls under concurrency: reserve atomically holds quota with a 60s TTL; commit confirms after the call succeeds; release rolls back on error.
TermLimit group
The basic unit of quota in AIPricingLab: a label, a unit, a quota, a period, and a list of match rules that decide which events count toward it.
TermEnd-user
The user of YOUR AI app - the one whose AI consumption you are metering. Distinct from "user" (a developer logged into AIPricingLab) and "workspace" (a developer organization).
TermPeriod anchor
How a limit group decides when to reset. "calendar" resets on a fixed date (1st of month UTC). "subscription_start" resets on the user's subscription anniversary.
TermComposite event
A single tracked event (one apl.track call) that, via match rules, increments more than one limit group at the same time. The default model in AIPricingLab.
TermAPI key (sk_live_ vs pk_live_)
AIPricingLab apps have two key types. sk_live_… is a secret server-side key with full access. pk_live_… is a public client-side key that can ONLY read the calling user's own usage.
TermWebhook
A signed HTTP POST that AIPricingLab fires to your URL when something happens - a user crosses 80% of quota, a plan changes, a limit is hit. Idempotent, with replay.