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

# API Overview

> Learn how to use Jan's OpenAI-compatible local API server for private AI development.

## Introduction

Jan provides a built-in, OpenAI-compatible API server that runs entirely on your computer, powered by `llama.cpp`. Use it as a drop-in replacement for cloud APIs to build private, offline-capable AI applications.

The API server is accessible at `http://127.0.0.1:1337` by default and follows OpenAI's API conventions.

## Base URL

```
http://127.0.0.1:1337/v1
```

## Authentication

All API requests require authentication using a Bearer token in the `Authorization` header.

### Setting up Authentication

1. Navigate to **Settings** > **Local API Server** in Jan
2. Enter a custom **API Key** (e.g., `secret-key-123`)
3. Click **Start Server**

### Using the API Key

Include the API key in all requests:

```bash theme={null}
Authorization: Bearer YOUR_API_KEY
```

### Example Request

```bash theme={null}
curl http://127.0.0.1:1337/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer secret-key-123" \
  -d '{
    "model": "llama3-8b-instruct",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'
```

## Server Configuration

### Network Settings

<ParamField path="host" type="string" default="127.0.0.1">
  The network address the server listens on.

  * `127.0.0.1`: Accessible only from your computer (most secure)
  * `0.0.0.0`: Accessible from other devices on your network
</ParamField>

<ParamField path="port" type="number" default="1337">
  The port number for the API server. You can change this to any available port (e.g., `8000`).
</ParamField>

<ParamField path="api_prefix" type="string" default="/v1">
  The base path for all API endpoints. Follows OpenAI's convention.
</ParamField>

### Security Settings

<ParamField path="api_key" type="string" required>
  A mandatory secret key to authenticate requests. Must be included in the `Authorization: Bearer YOUR_API_KEY` header for all requests.
</ParamField>

<ParamField path="trusted_hosts" type="string">
  A comma-separated list of hostnames allowed to access the server. Provides an additional layer of security when the server is exposed on your network.
</ParamField>

### Advanced Settings

<ParamField path="cors" type="boolean" default={true}>
  Enables Cross-Origin Resource Sharing (CORS) to allow web applications running on different domains to make requests to the API server. Disable for non-browser-based applications.
</ParamField>

<ParamField path="verbose_logs" type="boolean" default={true}>
  Provides detailed, real-time logs of all incoming requests, responses, and server activity. Useful for debugging.
</ParamField>

## Available Endpoints

<CardGroup cols={2}>
  <Card title="Chat Completions" icon="comments" href="/api/chat-completions">
    Generate chat completions with streaming support
  </Card>

  <Card title="Models" icon="cube" href="/api/models">
    List and retrieve available models
  </Card>

  <Card title="Embeddings" icon="vector-square" href="/api/embeddings">
    Generate embeddings for text inputs
  </Card>
</CardGroup>

## Error Handling

The API uses standard HTTP status codes:

* `200` - Success
* `400` - Bad Request (invalid parameters)
* `401` - Unauthorized (missing or invalid API key)
* `404` - Not Found (model not available)
* `500` - Internal Server Error

### Error Response Format

```json theme={null}
{
  "error": {
    "message": "Error description",
    "type": "invalid_request_error",
    "code": "model_not_found"
  }
}
```

## Troubleshooting

### Connection Refused

The server is not running, or your application is pointing to the wrong host or port.

### 401 Unauthorized

Your API Key is missing from the `Authorization` header or is incorrect.

### 404 Not Found

* The `model` ID in your request body does not match an available model in Jan
* Your request URL is incorrect (check the API Prefix)

### CORS Error (in web browser)

Ensure the CORS toggle is enabled in Jan's settings.

### Out of Context

The conversation has exceeded the model's context window. The API will return a `finish_reason` of `length`.