> ## Documentation Index
> Fetch the complete documentation index at: https://www.narev.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Billing integrations

> Send AI-billing usage events from your app to Polar, Stripe, Lago, or OpenMeter.

AI-billing captures usage inside your app, resolves cost, and sends events to your chosen destination. Configure credentials, customer identity, and meters in your app and billing service.

Start with the [quickstart](https://www.narev.ai/docs/ai-billing/quickstart.md) and [Node.js integration](https://www.narev.ai/docs/ai-billing/integrations/frameworks/nodejs.md). Use Customer Tagging from authenticated server state so each event maps to the right customer.

> **[Polar](https://www.narev.ai/docs/ai-billing/integrations/billing-platforms/polar.md)**
>
> Send events with costs in base currency units and map customer external IDs.

> **[Stripe](https://www.narev.ai/docs/ai-billing/integrations/billing-platforms/stripe.md)**
>
> Configure a destination, meter units, and Stripe customer mapping.

> **[Lago](https://www.narev.ai/docs/ai-billing/integrations/billing-platforms/lago.md)**
>
> Send usage to a billable metric with a matching customer identifier.

> **[OpenMeter](https://www.narev.ai/docs/ai-billing/integrations/billing-platforms/openmeter.md)**
>
> Send CloudEvents and configure the matching meter and customer subject.

## Pricing source

Use provider-reported costs, a static price map, or a compatible price resolver. The [Pricing API](https://www.narev.ai/docs/pricing-api/index.md) supplies public catalog rates and request cost calculations. A static map needs explicit updates when rates change.

You can also call the Pricing API directly from another stack and send the calculated amount to your billing service yourself. Recording provider cost and choosing what to charge a customer are separate decisions.


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