# Source: https://docs.pipecat.ai/server/services/tts/asyncai.md

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

# Async

> Text-to-speech services using Async's WebSocket and HTTP APIs

## Overview

Async provides high-quality text-to-speech synthesis with two service implementations: `AsyncAITTSService` (WebSocket-based) for real-time streaming with interruption support, and `AsyncAIHttpTTSService` (HTTP-based) for simpler synthesis. `AsyncAITTSService` is recommended for interactive applications requiring low latency.

<CardGroup cols={2}>
  <Card title="AsyncAI TTS API Reference" icon="code" href="https://reference-server.pipecat.ai/en/latest/api/pipecat.services.asyncai.tts.html">
    Pipecat's API methods for AsyncAI TTS integration
  </Card>

  <Card title="Example Implementation" icon="play" href="https://github.com/pipecat-ai/pipecat/blob/main/examples/foundational/07zc-interruptible-asyncai.py">
    Complete example with WebSocket streaming
  </Card>

  <Card title="Async Documentation" icon="book" href="https://docs.async.ai/">
    Official Async API documentation
  </Card>

  <Card title="Voice Models" icon="microphone" href="https://async.ai/">
    Explore available voice models and features
  </Card>
</CardGroup>

## Installation

To use Async services, install the required dependencies:

```bash  theme={null}
pip install "pipecat-ai[asyncai]"
```

## Prerequisites

### Async Account Setup

Before using Async TTS services, you need:

1. **Async Account**: Sign up at [Async](https://async.ai)
2. **API Key**: Generate an API key from your account dashboard
3. **Voice Selection**: Choose from available voice models

### Required Environment Variables

* `ASYNCAI_API_KEY`: Your Async API key for authentication