Merge pull request #4460 from janhq/chore/update-api-server-docs

Chore: Updated Local API Server Docs

Author: ux-han

docs/src/pages/docs/_assets/api-server.png

@@ -23,6 +23,7 @@
   "assistants": "Assistants",
   "threads": "Threads",
   "settings": "Settings",
+  "api-server": "Local API Server",
   "inference-engines": {
     "title": "ENGINES",
     "type": "separator"

docs/src/pages/docs/_meta.json

@@ -0,0 +1,123 @@
+---
+title: Local API Server
+description: Learn how to run Jan's local API server.
+  [
+    Jan,
+    Customizable Intelligence, LLM,
+    local AI,
+    privacy focus,
+    free and open source,
+    private and offline,
+    conversational AI,
+    no-subscription fee,
+    large language models,
+    Jan Extensions,
+    Extensions,
+  ]
+---
+
+import { Callout, Steps } from 'nextra/components'
+import { Settings, EllipsisVertical } from 'lucide-react'
+
+# Local API Server
+
+Jan includes a built-in API server that is compatible with OpenAI's API specification, allowing you to interact with AI models through a local HTTP interface. This means you can use Jan as a drop-in replacement for OpenAI's API, but running entirely on your computer.
+
+Jan uses **Cortex** as its core engine for running AI models. If you need a standalone API server without Jan's desktop interface (for example, in server environments or for command-line usage), you can use Cortex directly: https://cortex.so.
+
+<Callout>
+Full API documentation is available at [Cortex's API Reference](https://cortex.so/api-reference#tag/chat).
+</Callout>
+
+<br/>
+![Local API Server](./_assets/api-server.png)
+<br/>
+
+## Start Server
+
+<Steps>
+
+### Step 1: Start Server
+1. Navigate to the **Local API Server**
+2. Configure [Server Settings](/docs/api-server#server-settings)
+3. Click **Start Server** button
+4. Wait for the confirmation message in the logs panel, your server is ready when you see: `JAN API listening at: http://127.0.0.1:1337`
+
+
+### Step 2: Test Server
+The easiest way to test your server is through the API Playground:
+1. Click the **API Playground** button to open its testing interface
+2. Select a model from the dropdown menu in Jan interface
+3. Try a simple [chat completion](https://cortex.so/api-reference#tag/chat/post/v1/chat/completions) request
+4. View the response in real-time
+
+### Step 3: Use the API 
+Navigate to [Cortex's API Reference](https://cortex.so/api-reference#tag/chat) to see full API endpoints for your use case.
+</Steps>
+
+
+## Server Settings
+
+#### Host Address Options
+- **127.0.0.1 (Recommended)**: 
+  - Only accessible from your computer
+  - Most secure option for personal use
+- **0.0.0.0**: 
+  - Makes server accessible from other devices on your network
+  - Use with caution and only when necessary
+
+#### Port Number
+- Default: `1337`
+- Can be any number between 1-65535
+- Avoid common ports (80, 443, 3000, 8080) that might be used by other applications
+
+#### API Prefix
+- Default: `/v1`
+- Defines the base path for all API endpoints
+- Example: http://127.0.0.1:1337/v1/chat/completions
+
+#### Cross-Origin Resource Sharing (CORS)
+CORS controls which websites can access your API, which is important for web applications running in browsers.
+
+**When to enable:**
+- If you're building a web application that needs to access the API
+- If you're using browser extensions
+
+**When to leave disabled:**
+- If you're only using the API from your local applications
+- If you're concerned about security
+
+#### Verbose Server Logs
+Enable to show:
+- Detailed information about each API request
+- Error messages and debugging information
+- Server status updates
+
+## Troubleshooting Guide
+
+<Callout>
+Enable **Verbose Server Logs** for detailed error messages.
+</Callout>
+
+**1. Common Issues**
+   - Confirm the server is running
+   - Check if model is successfully loaded in Jan
+
+   - Check if the port is already in use by another application
+   - Verify you have admin/sudo rights if needed
+   - Make sure your API endpoint matches your server settings. Example: Using `http://localhost:1337` when you set a different port.
+   - Make sure the model name in your API request matches exactly what's shown in Jan. Example: If you selected "Llama 3.2 1B Instruct Q8" in Jan, use `llama3.2-1b-instruct` in your API request.
+   - Verify your JSON request format is correct
+   - Verify firewall settings
+   - Look for detailed error messages in the logs
+
+**2. CORS Errors in Web Apps**
+   - Enable CORS in server settings if using from a webpage
+   - Verify the origin of the request
+   - Verify your web app's request URL matches the server address exactly
+   - Check browser console for specific error messages
+
+**3. Performance Issues**
+   - Monitor system resources (CPU, RAM, and GPU usage)
+   - Try to reduce the context length or `ngl` (number of GPU layers)
+   - Check for other resource-intensive applications