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

# Emissions API

> Everything you need to integrate TerraTwin into your systems.

<Card title="Emissions API" icon="rocket" href="/api-reference/calculate-transport-emissions" horizontal>
  Explore the Emissions API endpoints, request/response formats, and end-to-end examples.
</Card>

## Getting started

<Columns cols={2}>
  <Card title="How credits work" icon="map" href="/credits">
    Learn how credits are consumed per shipment leg, how usage is calculated, and how to avoid surprises in production.
  </Card>

  <Card title="Setting up API keys" icon="terminal" href="/authentication">
    Generate API keys, lock them down, and wire them into your services so every request is authenticated by default.
  </Card>
</Columns>