Core Concepts

The building blocks of Nozle. Each concept maps to a specific part of the platform -- understand these and the rest of the docs will click.

Plans

A plan is a pricing tier -- Starter, Growth, Scale, Enterprise, or whatever you define. Each plan bundles three things:

• Base price -- a flat recurring charge (monthly or annual)
• Usage-based charges -- metered fees tied to event codes (e.g., $0.002 per API call)
• Feature entitlements -- what the plan unlocks (analytics access, SSO, custom models)

Plans are configured in the Nozle dashboard and served to your app through the API.

Subscriptions

A subscription assigns a customer to a plan. When a customer checks out, Nozle creates a subscription that controls what they can access and how they are billed.

Subscriptions support:

• Upgrades -- move to a higher plan mid-cycle with prorated charges
• Downgrades -- move to a lower plan, effective at the next billing period
• Cancellation -- end the subscription with prorated credits

Events

Events are usage data points sent from your application via the SDK's track() method. Each event contains:

The event pipeline flows: SDK → Nozle API → aggregation and billing.

Events drive both usage-based charges and entitlement consumption (counting toward limits).

Entitlements

Entitlements define what a customer can do based on their plan. There are two types:

Feature gates -- boolean access checks. Either the plan includes a feature or it does not.

can("analytics")       // → true or false
can("custom-models")   // → true or false

Usage limits -- numeric caps that reset each billing period.

can("api-calls")       // → { allowed: true, remaining: 8420 }
can("team-members")    // → { allowed: false, remaining: 0 }

Entitlements are checked via the can() endpoint (REST) or the useCan() hook (React SDK). Updates propagate in real-time over WebSocket -- no polling required.

Margin

Margin intelligence is what separates Nozle from a billing system. Nozle tracks the cost of each usage unit -- per LLM model, per token type, per provider -- and compares it against what you charge.

This gives you:

• Per-customer margin -- who is profitable, who is not
• Per-model cost tracking -- which models eat into margin
• Alerts -- get notified when margin drops below a threshold

Margin data is computed by the Nozle API and returned alongside billing data.

API Keys

Nozle uses two types of API keys to separate client-safe and server-only operations: