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

# Getting Started

Welcome to the Loop Returns API! This documentation is your guide to integrating with Loop. Browse the documentation to learn how to make requests, create and manage webhooks, and more.

## Using the API

### Authentication

Requests to the Loop API require a valid API key. The API key should be passed in the `X-Authorization` header. For more details, read the [Authentication documentation](/api-reference/authentication).

### Popular APIs

<CardGroup cols={2}>
  <Card title="Return Data" icon="code" href="/api-reference/latest/return-data/get-return-details">
    Pull detailed information for one or more returns.
  </Card>

  <Card title="Return Actions" icon="flag" href="/api-reference/latest/return-actions/process-return">
    Execute actions on returns such as processing and flagging.
  </Card>
</CardGroup>

## Additive Changes

Loop may add new fields to API responses at any time without prior notice. These changes are additive only: we do not change the meaning of existing fields, change field types, or remove fields. Build your integration so that unknown or extra fields in the response do not cause failures (for example, avoid strict schema validation that rejects additional properties).