docs: update for pipecat PR #4092

docs.json

@@ -202,6 +202,7 @@
                   "server/services/tts/resembleai",
                   "server/services/tts/rime",
                   "server/services/tts/sarvam",
+                  "server/services/tts/smallest",
                   "server/services/tts/speechmatics",
                   "server/services/tts/xtts"
                 ]

server/services/supported-services.mdx

@@ -110,6 +110,7 @@ Text-to-Speech services receive text input and output audio streams or chunks.
 | [ResembleAI](/server/services/tts/resembleai)     | `pip install "pipecat-ai[resembleai]"`   |
 | [Rime](/server/services/tts/rime)                 | `pip install "pipecat-ai[rime]"`         |
 | [Sarvam](/server/services/tts/sarvam)             | No dependencies required                 |
+| [Smallest AI](/server/services/tts/smallest)      | `pip install "pipecat-ai[smallest]"`     |
 | [Speechmatics](/server/services/tts/speechmatics) | `pip install "pipecat-ai[speechmatics]"` |
 | [XTTS](/server/services/tts/xtts)                 | `pip install "pipecat-ai[xtts]"`         |
 

server/services/tts/smallest.mdx

@@ -0,0 +1,175 @@
+---
+title: "Smallest AI"
+description: "Text-to-speech service using Smallest AI's WebSocket streaming API"
+---
+
+## Overview
+
+Smallest AI provides real-time text-to-speech synthesis through a WebSocket-based integration with their Waves API. The service supports configurable voice parameters, multiple languages, and handles interruptions by reconnecting the WebSocket.
+
+<CardGroup cols={2}>
+  <Card
+    title="Smallest AI TTS API Reference"
+    icon="code"
+    href="https://reference-server.pipecat.ai/en/latest/api/pipecat.services.smallest.tts.html"
+  >
+    Complete API reference for all parameters and methods
+  </Card>
+  <Card
+    title="Example Implementation"
+    icon="play"
+    href="https://github.com/pipecat-ai/pipecat/blob/main/examples/foundational/07zl-interruptible-smallest.py"
+  >
+    Complete example with WebSocket streaming
+  </Card>
+</CardGroup>
+
+## Installation
+
+```bash
+pip install "pipecat-ai[smallest]"
+```
+
+## Prerequisites
+
+1. **Smallest AI Account**: Sign up at [Smallest AI](https://www.smallest.ai/)
+2. **API Key**: Generate an API key from your account dashboard
+
+Set the following environment variable:
+
+```bash
+export SMALLEST_API_KEY=your_api_key
+```
+
+## Configuration
+
+<ParamField path="api_key" type="str" required>
+  Smallest AI API key for authentication.
+</ParamField>
+
+<ParamField path="base_url" type="str" default="wss://waves-api.smallest.ai">
+  Base WebSocket URL for the Smallest API. Override for custom or proxied
+  deployments.
+</ParamField>
+
+<ParamField path="sample_rate" type="int" default="None">
+  Output audio sample rate in Hz. When `None`, uses the pipeline's configured
+  sample rate.
+</ParamField>
+
+<ParamField path="settings" type="SmallestTTSService.Settings" default="None">
+  Runtime-configurable settings. See [Settings](#settings) below.
+</ParamField>
+
+### Settings
+
+Runtime-configurable settings passed via the `settings` constructor argument using `SmallestTTSService.Settings(...)`. These can be updated mid-conversation with `TTSUpdateSettingsFrame`. See [Service Settings](/guides/fundamentals/service-settings) for details.
+
+| Parameter     | Type              | Default            | Description                                                                                                                |
+| ------------- | ----------------- | ------------------ | -------------------------------------------------------------------------------------------------------------------------- |
+| `model`       | `str`             | `lightning-v3.1`   | Model identifier: `lightning-v2` or `lightning-v3.1`. Model changes require WebSocket reconnection. _(Init-only setting)_ |
+| `voice`       | `str`             | `sophia`           | Voice identifier.                                                                                                          |
+| `language`    | `Language \| str` | `Language.EN`      | Language code for synthesis.                                                                                               |
+| `speed`       | `float`           | `None`             | Speech speed multiplier. When `None`, uses API defaults.                                                                   |
+| `consistency` | `float`           | `None`             | Consistency level for voice generation (0-1). Only supported by `lightning-v2`. When `None`, uses API defaults.            |
+| `similarity`  | `float`           | `None`             | Similarity level for voice generation (0-1). Only supported by `lightning-v2`. When `None`, uses API defaults.             |
+| `enhancement` | `int`             | `None`             | Enhancement level for voice generation (0-2). Only supported by `lightning-v2`. When `None`, uses API defaults.            |
+
+<Note>
+  `None` values use the Smallest AI API defaults. The `consistency`,
+  `similarity`, and `enhancement` parameters are only supported by the
+  `lightning-v2` model.
+</Note>
+
+## Usage
+
+### Basic Setup
+
+```python
+from pipecat.services.smallest import SmallestTTSService
+
+tts = SmallestTTSService(
+    api_key=os.getenv("SMALLEST_API_KEY"),
+    settings=SmallestTTSService.Settings(
+        voice="sophia",
+    ),
+)
+```
+
+### With Voice Customization
+
+```python
+from pipecat.transcriptions.language import Language
+
+tts = SmallestTTSService(
+    api_key=os.getenv("SMALLEST_API_KEY"),
+    settings=SmallestTTSService.Settings(
+        voice="sophia",
+        language=Language.ES,
+        speed=1.2,
+    ),
+)
+```
+
+### Using Lightning V2 Model
+
+```python
+from pipecat.services.smallest.tts import SmallestTTSModel
+
+tts = SmallestTTSService(
+    api_key=os.getenv("SMALLEST_API_KEY"),
+    settings=SmallestTTSService.Settings(
+        model=SmallestTTSModel.LIGHTNING_V2,
+        voice="sophia",
+        consistency=0.7,
+        similarity=0.8,
+        enhancement=1,
+    ),
+)
+```
+
+### Updating Settings at Runtime
+
+Voice settings can be changed mid-conversation using `TTSUpdateSettingsFrame`:
+
+```python
+from pipecat.frames.frames import TTSUpdateSettingsFrame
+from pipecat.services.smallest.tts import SmallestTTSSettings
+
+await task.queue_frame(
+    TTSUpdateSettingsFrame(
+        delta=SmallestTTSSettings(
+            voice="new_voice",
+            speed=1.1,
+        )
+    )
+)
+```
+
+<Tip>
+  Changing the `model` setting will trigger a WebSocket reconnection, which may
+  cause a brief interruption in service.
+</Tip>
+
+## Notes
+
+- **WebSocket streaming**: The service uses WebSocket connections for real-time streaming. The connection is automatically managed and will reconnect if interrupted.
+- **Keepalive**: The service sends periodic keepalive messages (every 30 seconds) to prevent idle timeouts on the WebSocket connection.
+- **Model-specific parameters**: The `consistency`, `similarity`, and `enhancement` parameters are only effective when using the `lightning-v2` model. They are ignored by `lightning-v3.1`.
+- **Language support**: Supports multiple languages including Arabic, Bengali, German, English, Spanish, French, Gujarati, Hebrew, Hindi, Italian, Kannada, Marathi, Dutch, Polish, Russian, and Tamil.
+
+## Event Handlers
+
+Smallest AI TTS supports the standard [service connection events](/server/utilities/service-events):
+
+| Event                 | Description                         |
+| --------------------- | ----------------------------------- |
+| `on_connected`        | Connected to Smallest AI WebSocket  |
+| `on_disconnected`     | Disconnected from Smallest WebSocket |
+| `on_connection_error` | WebSocket connection error occurred |
+
+```python
+@tts.event_handler("on_connected")
+async def on_connected(service):
+    print("Connected to Smallest AI")
+```