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

# API Reference

> REST API reference for Document Understanding (Dex) — projects, files, parse, extract, and vector stores.

The Document Understanding API provides REST endpoints for document processing. Use the API for non-Python integrations or when you need direct control over HTTP requests.

Browse the full REST API in the **[Dex API](/reference/dex)** tab. Key endpoint groups:

| Group             | Description                                     |
| ----------------- | ----------------------------------------------- |
| **Projects**      | Create, list, and manage projects               |
| **Files**         | Upload files, get download URLs, stream content |
| **Parse**         | Create parse jobs, list results, rechunk        |
| **Extract**       | Create extract jobs, list extractions           |
| **Vector Stores** | Create stores, add files, search                |
| **Jobs**          | Get job status and monitor progress             |

***

## Authentication

All requests require:

* **`x-api-key`**: Your SGP API key
* **`x-selected-account-id`**: Your SGP account ID

```bash theme={null}
curl -X GET "https://dex.sgp.scale.com/v1/projects" \
  -H "x-api-key: $SGP_API_KEY" \
  -H "x-selected-account-id: $SGP_ACCOUNT_ID"
```

***

## Base URL

| Environment | Base URL                    |
| ----------- | --------------------------- |
| Production  | `https://dex.sgp.scale.com` |

***

## Next Steps

* **[Getting Started](getting-started-with-dex)**: Step-by-step tutorial with the Python SDK
* **[Dex SDK API Reference](dex-sdk-api-reference)**: Python SDK methods and types
* **[Best Practices](best-practices)**: Optimization and common patterns