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

# Rei Chat API and SDK

> Integrate the conversational Rei Chat surface, manage Units, and call its inference APIs.

Use the Rei Chat API when an application needs the conversational surface around Core. Core maintains and revises the reasoning state; the language layer renders Core's structured result as a human-readable response.

## Start here

Begin with the [Quickstart](/docs/api-and-sdk/quickstart) to authenticate, choose the correct base URL, and make the first call.

## Choose an integration path

| I need to...                           | Start with                                                                                 |
| -------------------------------------- | ------------------------------------------------------------------------------------------ |
| Make the first Rei Chat request        | [Quickstart](/docs/api-and-sdk/quickstart)                                                 |
| Use an existing package interface      | [SDK](/docs/api-and-sdk/sdk)                                                               |
| Add Rei Chat to another agent          | [Integration with existing agents](/docs/api-and-sdk/integration-with-existing-agents)     |
| Add Rei Chat to an application service | [Integration with existing services](/docs/api-and-sdk/integration-with-existing-services) |

## API surfaces

The Rei Chat API uses separate base URLs for separate responsibilities:

* `https://rei-api.reilabs.org/v1` handles chat inference.
* `https://api.reilabs.org/v1` handles Unit and agent management.

Use the endpoint under the hostname shown in its reference section. Do not combine a path from one surface with the other base URL.