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

# Aero TTS

> thinnestAI's text-to-speech engine — 5 models, 90+ voices, 20+ languages with ultra-low latency.

# Aero TTS

Aero TTS is thinnestAI's built-in text-to-speech engine. Convert any text into natural, human-sounding speech with ultra-low latency — perfect for voice agents, IVR systems, accessibility features, and content creation.

## Why Aero TTS?

* **Ultra-low latency** — \~60-120ms time-to-first-byte depending on model
* **90+ voices** — Male and female voices across 20+ languages
* **3 model tiers** — From premium high-quality to lightweight cost-effective models
* **Voice mixing** — Blend multiple voices to create unique custom voices
* **Streaming** — Start playback before synthesis completes
* **Simple API** — One endpoint, one API key, any programming language
* **Pay-as-you-go** — Billed per character with generous free tier

## Models

Aero TTS offers 3 models optimized for different use cases:

| Model         | Latency | Quality | Best For                               |
| ------------- | ------- | ------- | -------------------------------------- |
| **aero**      | \~100ms | Highest | Production voice agents, phone calls   |
| **aero-mini** | \~200ms | Medium  | Cost-effective batch processing        |
| **aero-nano** | \~150ms | Medium  | Lightweight, low-resource environments |

### Choosing a Model

* **Voice agents / phone calls** — Use `aero` for the most natural, lowest-latency output
* **High-volume batch jobs** — Use `aero-mini` for cost-effective processing
* **Lightweight usage** — Use `aero-nano` for minimal resource usage

## Supported Languages

| Language     | Code           | Models                     |
| ------------ | -------------- | -------------------------- |
| English (US) | `en-us`        | aero, aero-mini, aero-nano |
| English (UK) | `en-gb`        | aero, aero-mini, aero-nano |
| Hindi        | `hi` / `hi-in` | aero                       |
| Spanish      | `es`           | aero-mini, aero-nano       |
| French       | `fr`           | aero-mini, aero-nano       |
| German       | `de`           | aero-mini, aero-nano       |
| Italian      | `it`           | aero-mini, aero-nano       |
| Chinese      | `zh`           | aero-mini, aero-nano       |
| Japanese     | `ja`           | aero-mini, aero-nano       |
| Korean       | `ko`           | aero-mini, aero-nano       |
| Portuguese   | `pt`           | aero-mini, aero-nano       |

## Quick Start

### 1. Get an API Key

Go to the **Aero TTS** page in your thinnestAI dashboard and click **API Keys** > **Create Key**.

### 2. Synthesize Speech

```bash theme={null}
curl -X POST https://api.thinnest.ai/api/tts/synthesize \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "text": "Hello! Welcome to Aero TTS.",
    "voice": "aero-vayu",
    "model": "aero",
    "format": "mp3"
  }' \
  --output speech.mp3
```

### 3. Play the Audio

```bash theme={null}
# macOS
afplay speech.mp3

# Linux
aplay speech.mp3

# Windows
start speech.mp3
```

That's it. You now have natural-sounding speech from text.

## Audio Formats

| Format | Extension | Use Case                            |
| ------ | --------- | ----------------------------------- |
| `mp3`  | `.mp3`    | Web playback, general use (default) |
| `wav`  | `.wav`    | Lossless, professional audio        |
| `pcm`  | `.pcm`    | Raw audio for real-time pipelines   |
| `opus` | `.opus`   | Low-bandwidth streaming             |
| `ogg`  | `.ogg`    | Open-source applications            |
| `flac` | `.flac`   | Lossless compression                |
| `aac`  | `.aac`    | Mobile and Apple ecosystem          |

## Dashboard

The Aero TTS dashboard in thinnestAI provides:

* **Playground** — Type text and hear it spoken instantly. Compare voices and models side by side.
* **Voices** — Browse all 90+ voices, filter by language and gender, preview samples.
* **Voice Lab** — Create custom hybrid voices by blending 2-4 voices together.
* **API Keys** — Create, manage, and revoke API keys with per-key rate limits.
* **Usage** — Track character usage, request counts, latency metrics, and costs.

## Next Steps

* [Voices](/docs/aero-tts/voices) — Browse all available voices by language and gender
* [API Reference](/docs/aero-tts/api) — Full REST API documentation with examples
* [Voice Lab](/docs/aero-tts/voice-lab) — Create custom hybrid voices
* [Pricing](/docs/aero-tts/pricing) — Understand pricing tiers and free allowances
* [SDKs & Integration](/docs/aero-tts/sdks) — Python, JavaScript, and cURL examples