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

# Cloud API Reference

> Cloud API reference for Nimbus authentication, licensing, model registry, and backend endpoints used by the Julia SDK.

# Nimbus API

The Nimbus API provides backend services for the Julia SDK (NimbusSDK.jl), including:

* **Authentication**: API key validation and licensing (Julia SDK only)
* **Model Registry**: Access to pre-trained models (Julia SDK only)
* **Analytics**: Usage tracking and performance metrics
* **Quota Management**: License-based usage limits

<Note>
  **Python SDK Users**: The Python SDK (`nimbus-bci`) does **not** require API keys or API access. All processing is local. See the [Python SDK documentation](/python-sdk/introduction) for details.
</Note>

## Start Here

<CardGroup cols={3}>
  <Card title="Authentication" icon="key" href="/cloud-api/authentication">
    Validate API keys, quotas, and license behavior.
  </Card>

  <Card title="Endpoints" icon="list" href="/cloud-api/inference-endpoints">
    Review model registry and analytics API routes.
  </Card>

  <Card title="Julia Setup" icon="code" href="/julia-sdk/quickstart">
    Install NimbusSDK.jl and enable authenticated workflows.
  </Card>
</CardGroup>

## API Base URL

```
https://api.nimbusbci.com
```

## Authentication

All API requests require authentication via API key. Prefer the `X-API-Key` header for server-to-server calls:

* Header: `X-API-Key: nbci_live_...`
* JSON body parameter: `"api_key": "nbci_live_..."` for POST endpoints that accept a request body

Some GET endpoints also accept `?api_key=nbci_live_...` for compatibility. Avoid query-string keys in production because URLs are commonly captured in logs, browser history, proxies, and referrer headers.

### API Key Format

* **Production keys**: `nbci_live_` + 48 hex characters
* **Test keys**: `nbci_test_` + 48 hex characters

### License Tiers

| Tier           | Monthly Quota      | Features                        | Use Case                      |
| -------------- | ------------------ | ------------------------------- | ----------------------------- |
| **Free**       | 10,000 inferences  | Basic models, batch inference   | Personal projects, evaluation |
| **Research**   | 50,000 inferences  | All models, streaming, training | Academic research             |
| **Commercial** | 500,000 inferences | Priority support, custom models | Production applications       |
| **Enterprise** | Unlimited          | Dedicated support, on-premise   | Large-scale deployments       |

## SDK Comparison

| Feature              | Python SDK              | Julia SDK                 |
| -------------------- | ----------------------- | ------------------------- |
| **API Key Required** | ❌ No                    | ✅ Yes                     |
| **API Access**       | Not needed              | Required for installation |
| **Authentication**   | None                    | Via API key               |
| **Model Registry**   | Not available           | Pre-trained models        |
| **Licensing**        | Proprietary (free eval) | Commercial tiers          |

## SDK Setup

This page documents the backend API scope and endpoint surface. For the Julia installation and first-inference walkthrough, use the [Julia SDK Quickstart](/julia-sdk/quickstart). For Python, no API setup is required; install `nimbus-bci` from the [Python SDK Quickstart](/python-sdk/quickstart).

## Endpoints Overview

The Nimbus API provides the following endpoints:

* **Authentication**: `/v1/auth/validate`, `/v1/auth/refresh`, `/v1/auth/revoke`
* **SDK Installation**: `/v1/installer/github-token`
* **Models**: `/v1/models/list`
* **Analytics**: `/v1/analytics/log`
* **Health**: `/api/health`

Detailed documentation for each endpoint is available in the following pages.

## Next Read

<CardGroup cols={2}>
  <Card title="Python SDK" icon="python" href="/python-sdk/introduction">
    No API key needed - get started immediately
  </Card>

  <Card title="Julia SDK" icon="code" href="/julia-sdk/api-reference">
    Complete Julia SDK reference (requires API key)
  </Card>

  <Card title="Authentication" icon="key" href="/cloud-api/authentication">
    API key validation and management (Julia SDK)
  </Card>

  <Card title="Model Registry" icon="database" href="/cloud-api/inference-endpoints">
    Pre-trained models (Julia SDK)
  </Card>
</CardGroup>

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