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

# Introduction

> **Sell Agent** API Documentation Overview and Authentication Setup

## 👋 Welcome to the Sell Agent API Documentation

This API enables seamless integration with your **Voice-Based AI Agents** and **Telephony System**. Whether you're building a custom interface, automating call flows, or managing agent configurations programmatically — this API gives you complete control.

## 🔐 Getting Started with Authentication

To begin using the API, you’ll need an **API Key** for secure access.\
All endpoints require the `x-api-key` header for authentication.

📽️ **Watch the video below** to learn how to create your **Sell Agent** API key and get started in minutes.

<iframe width="100%" height="400" src="https://www.youtube.com/embed/Cu9cspF1DXo" frameBorder="0" allowFullScreen />

> After generating your API key, you can use it along with the optional `x-workspace-id` header to interact with:
>
> * AI Voice Agents
> * SIP-enabled Phone Numbers
> * Outbound Call Initiation
> * Call Log Retrieval & Filtering

## 🛡️ Authentication Requirements

All API requests must include the following headers:

> * x-api-key: YOUR\_API\_KEY\_HERE
> * Content-Type: application/json