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

# Introduction

> Echo is an AI-powered voice notification platform. One API call initiates a real phone call that can hold a full conversation with your user.

## What is Echo?

Most notification systems are one-way — you fire a message and hope someone sees it. Echo is different. Echo calls your users and **talks back**.

Depending on how you configure it, Echo can deliver a brief appointment reminder, conduct a full intake survey, collect feedback, answer follow-up questions, and relay structured results back to your system via webhook.

The same API handles the full spectrum:

<CardGroup cols={3}>
  <Card title="Simple delivery" icon="bell">
    A 15-second "your order has shipped" call that ends cleanly.
  </Card>

  <Card title="Confirmation" icon="calendar-check">
    "Confirm your appointment" — reschedules automatically if the time doesn't work.
  </Card>

  <Card title="Data collection" icon="clipboard-list">
    A full intake survey that walks users through a form end-to-end.
  </Card>
</CardGroup>

## Two ways to trigger a call

<CardGroup cols={2}>
  <Card title="Agent path" icon="robot" href="/guides/agent-approach">
    Define a reusable voice persona with a system prompt and `{{variable}}` placeholders. Full control over tone, scope, and structured output extraction.
  </Card>

  <Card title="LLM path" icon="wand-magic-sparkles" href="/guides/llm-approach">
    Send a plain `message` string. Echo generates the call script on the fly using your business context. Zero configuration.
  </Card>
</CardGroup>

## Core concepts

Echo is structured around three objects:

| Concept      | Description                                                                                                                                    |
| ------------ | ---------------------------------------------------------------------------------------------------------------------------------------------- |
| **Business** | Your top-level account. Created at signup. Holds your agents and team members.                                                                 |
| **Project**  | An isolated environment within your business (e.g. `default`, `staging`). Has its own API key, customer pool, and notification history.        |
| **Agent**    | A reusable voice persona defined at the business level. Shared across all projects. Contains a system prompt with `{{variable}}` placeholders. |

## How a call works

```
Your server → POST /v1/notifications → Echo resolves agent + customer + variables
                                         → Renders the full prompt
                                         → Initiates the outbound call
                                         → Call happens in real time
                                         → Result POSTed to your webhook URL
```

## Start building

<CardGroup cols={2}>
  <Card title="Quickstart" icon="rocket" href="/quickstart">
    Sign up, create an agent, and send your first notification in minutes.
  </Card>

  <Card title="Agent approach" icon="robot" href="/guides/agent-approach">
    Learn how to build reusable voice agents with prompts and structured output.
  </Card>

  <Card title="Webhooks" icon="webhook" href="/guides/webhooks">
    Receive signed call results back on your server after every call.
  </Card>

  <Card title="API Reference" icon="square-terminal" href="/api-reference/introduction">
    Full endpoint reference with an interactive playground.
  </Card>
</CardGroup>