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

# Start here

> Find the right guide to estimate AI costs, track usage, bill customers, or evaluate cost reductions.

Choose a guide based on what you need to do. You can look up prices without integrating an SDK, connect usage tracking to an existing app, or follow a process for reducing production costs. The sidebar groups these tasks into the paths below.

## Estimate costs

Use these guides when you need to know what a request could cost or compare model and provider rates. Start with [searching model prices](./search-model-prices) if you need the correct identifiers. If you already know your model, provider, and token counts, go directly to [calculating a request's cost](./calculate-request-cost).

This path uses the Narev Cloud Pricing API. It includes provider comparisons and a DeepSeek example that explains cached-token costs. You don't need to run inference or install the Narev SDK.

## Track usage and bill customers

Choose the integration that matches your existing stack:

* [DeepSeek usage tracking](./deepseek-usage-based-billing): record usage and cost as your app generates responses.
* [Langfuse cost backfilling](./backfill-langfuse-costs): add cost estimates to generations you already recorded.
* [Chatbot with Polar billing](./chatbot-with-billing-polar): connect customer identity, usage events, and a billing meter.

Start by verifying the recorded cost. Before charging customers, also verify the customer mapping and meter units.

## Reduce AI costs

Start with the [FinOps for AI workflow](./finops-for-ai/index) when you need a plan for an existing workload. It takes you through setting objectives and ownership, understanding spending, and testing changes before releasing them.

The model-switch and prompt-engineering studies in this section show how to interpret cost and quality tradeoffs. Use them when you're ready to evaluate a specific change.

## Billing concepts

Read [AI pricing models](../platform/concepts/pricing-models) when you're deciding what customers should pay for. Continue with [usage-based billing](../platform/concepts/usage-based-billing) to understand how measured usage becomes a customer charge.


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