---
title: "FallbackTTS | Micdrop"
description: "The FallbackTTS class provides automatic failover between multiple TTS providers for improved reliability."
url: "https://micdrop.dev/docs/ai-integration/fallback-strategies/tts-fallback"
---

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# FallbackTTS

The `FallbackTTS` class provides automatic failover between multiple TTS providers for improved reliability. When one provider fails after exhausting its retries, it automatically switches to the next provider in the list.

## Features

*   **Automatic failover**: Seamlessly switches between providers when failures occur
*   **Text buffering**: Retains text chunks during failures and replays them to the next provider
*   **Circular rotation**: Cycles through providers indefinitely until speech synthesis succeeds
*   **Zero configuration**: Works with any TTS implementation
*   **Cancellation support**: Properly forwards cancel() calls to the active provider

## Usage

```
import { FallbackTTS } from '@micdrop/server'import { ElevenLabsTTS } from '@micdrop/elevenlabs'import { CartesiaTTS } from '@micdrop/cartesia'
// Create a fallback TTS with multiple providersconst tts = new FallbackTTS({  factories: [    // Primary provider: ElevenLabs with low retry count    () =>      new ElevenLabsTTS({        apiKey: process.env.ELEVENLABS_API_KEY || '',        voiceId: process.env.ELEVENLABS_VOICE_ID || '',        maxRetry: 2, // Fail faster to switch to backup      }),    // Backup provider: Cartesia    () =>      new CartesiaTTS({        apiKey: process.env.CARTESIA_API_KEY || '',        modelId: 'sonic-turbo',        voiceId: process.env.CARTESIA_VOICE_ID || '',        maxRetry: 3,      }),  ],})
// Use with MicdropServerconst server = new MicdropServer(socket, {  tts,  // ... other options})
```

## Options

Option

Type

Description

`factories`

`Array<() => TTS>`

Array of factory functions that create TTS instances

## How It Works

1.  **Initialization**: Starts with the first provider in the list
2.  **Normal operation**: Forwards all text to the current provider and emits audio chunks
3.  **On failure**: When a provider emits the `Failed` event:
    *   Destroys the current provider
    *   Moves to the next provider (wraps around to first if at end)
    *   Replays buffered text chunks to the new provider
4.  **Logging**: Inherits logger configuration and applies it to child providers

[Previous← FallbackSTT](/docs/ai-integration/fallback-strategies/stt-fallback)[NextLocal Models →](/docs/ai-integration/local-models)

On this page

*   [Features](#features)
*   [Usage](#usage)
*   [Options](#options)
*   [How It Works](#how-it-works)