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

# API Reference

Use the API reference to inspect Syntage endpoints, request parameters, response schemas, and examples. The API lets you work with organization entities and retrieve structured data from SAT, RPC, RUG, Buró de Crédito, Buró Empresas, Infonavit, and more.

## Base URLs

| Environment | Base URL                                                           |
| ----------- | ------------------------------------------------------------------ |
| Production  | [https://api.syntage.com](https://api.syntage.com)                 |
| Sandbox     | [https://api.sandbox.syntage.com](https://api.sandbox.syntage.com) |

Use sandbox for development and testing before production. All data returned in sandbox is simulated. See [Environments](/guides/api/environments) for more details.

## Authentication

Authenticate API requests with your API key in the `X-Api-Key` header.

```bash theme={null}
curl -i 'https://api.syntage.com/entities' \
  --header 'Accept: application/ld+json' \
  --header 'X-Api-Key: {apiKey}'
```

## Response format

Most API responses use [JSON-LD](https://json-ld.org). Collection responses include `hydra:member` and pagination metadata. See [Pagination](/guides/api/pagination), [Property Filtering](/guides/api/property-filtering), and [Entity URLs](/guides/api/entity-urls) for common API concepts.

## OpenAPI specification

Download the [OpenAPI specification](https://api.syntage.com/openapi.yaml) to generate clients or inspect the complete API surface.