RunwayML - Text-to-Speech

Overview

Property	Details
Description	RunwayML provides high-quality AI-powered text-to-speech with natural-sounding voices
Provider Route on LiteLLM	runwayml/
Supported Operations	/audio/speech
Link to Provider Doc	RunwayML API ↗

LiteLLM supports RunwayML's text-to-speech API with automatic task polling, allowing you to generate natural-sounding audio from text.

Quick Start

Basic Text-to-Speech

from litellm import speech
import os

os.environ["RUNWAYML_API_KEY"] = "your-api-key"

response = speech(
    model="runwayml/eleven_multilingual_v2",
    input="Step right up, ladies and gentlemen! Have you ever wished for a toaster that's not just a toaster but a marvel of modern ingenuity?",
    voice="alloy"
)

# Save the audio
with open("output.mp3", "wb") as f:
    f.write(response.content)

Authentication

Set your RunwayML API key:

Set API Key

import os

os.environ["RUNWAYML_API_KEY"] = "your-api-key"

Supported Parameters

Parameter	Type	Required	Description
model	string	Yes	Model to use (e.g., runwayml/eleven_multilingual_v2)
input	string	Yes	Text to convert to speech
voice	string or dict	Yes	Voice to use (OpenAI name, RunwayML preset, or voice config)

Voice Options

Using OpenAI Voice Names

OpenAI voice names are automatically mapped to appropriate RunwayML voices:

OpenAI Voice Names

from litellm import speech

# These OpenAI voice names work automatically
response = speech(
    model="runwayml/eleven_multilingual_v2",
    input="Hello, world!",
    voice="alloy"  # Maya - neutral, balanced female voice
)

Voice Mappings:

• alloy → Maya (neutral, balanced female voice)
• echo → James (male voice)
• fable → Bernard (warm, storytelling voice)
• onyx → Vincent (deep male voice)
• nova → Serene (warm, expressive female voice)
• shimmer → Ella (clear, friendly female voice)

Using RunwayML Preset Voices

You can directly specify any RunwayML preset voice by passing the preset name as a string:

RunwayML Preset Names

from litellm import speech

# Pass the RunwayML voice name as a string
response = speech(
    model="runwayml/eleven_multilingual_v2",
    input="Hello, world!",
    voice="Maya"  # LiteLLM automatically formats this for RunwayML
)

# Try different RunwayML voices
response = speech(
    model="runwayml/eleven_multilingual_v2",
    input="Step right up, ladies and gentlemen!",
    voice="Bernard"  # Great for storytelling
)

Available RunwayML Voices:

Maya, Arjun, Serene, Bernard, Billy, Mark, Clint, Mabel, Chad, Leslie, Eleanor, Elias, Elliot, Grungle, Brodie, Sandra, Kirk, Kylie, Lara, Lisa, Malachi, Marlene, Martin, Miriam, Monster, Paula, Pip, Rusty, Ragnar, Xylar, Maggie, Jack, Katie, Noah, James, Rina, Ella, Mariah, Frank, Claudia, Niki, Vincent, Kendrick, Myrna, Tom, Wanda, Benjamin, Kiana, Rachel

tip

Simply pass the voice name as a string - LiteLLM automatically handles the internal RunwayML API format conversion.

Async Usage

Async Text-to-Speech

from litellm import aspeech
import os
import asyncio

os.environ["RUNWAYML_API_KEY"] = "your-api-key"

async def generate_speech():
    response = await aspeech(
        model="runwayml/eleven_multilingual_v2",
        input="This is an asynchronous text-to-speech request.",
        voice="nova"
    )
    
    with open("output.mp3", "wb") as f:
        f.write(response.content)
    
    print("Audio generated successfully!")

asyncio.run(generate_speech())

LiteLLM Proxy Usage

Add RunwayML to your proxy configuration:

config.yaml

model_list:
  - model_name: runway-tts
    litellm_params:
      model: runwayml/eleven_multilingual_v2
      api_key: os.environ/RUNWAYML_API_KEY

Start the proxy:

litellm --config /path/to/config.yaml

Generate speech through the proxy:

Proxy Request

curl --location 'http://localhost:4000/v1/audio/speech' \
--header 'Content-Type: application/json' \
--header 'x-litellm-api-key: sk-1234' \
--data '{
    "model": "runwayml/eleven_multilingual_v2",
    "input": "Hello from the LiteLLM proxy!",
    "voice": "alloy"
}'

With RunwayML-specific voice:

Proxy Request with RunwayML Voice

curl --location 'http://localhost:4000/v1/audio/speech' \
--header 'Content-Type: application/json' \
--header 'x-litellm-api-key: sk-1234' \
--data '{
    "model": "runwayml/eleven_multilingual_v2",
    "input": "Hello with a custom RunwayML voice!",
    "voice": "Bernard"
}'

Supported Models

Model	Description
runwayml/eleven_multilingual_v2	High-quality multilingual text-to-speech

Cost Tracking

LiteLLM automatically tracks RunwayML text-to-speech costs:

Cost Tracking

from litellm import speech, completion_cost

response = speech(
    model="runwayml/eleven_multilingual_v2",
    input="Hello, world!",
    voice="alloy"
)

cost = completion_cost(completion_response=response)
print(f"Text-to-speech cost: ${cost}")

Supported Features

Feature	Supported
Text-to-Speech	✅
Cost Tracking	✅
Logging	✅
Fallbacks	✅
Load Balancing	✅
50+ Voice Presets	✅

How It Works

RunwayML uses an asynchronous task-based API pattern. LiteLLM handles the polling and response transformation automatically.

Complete Flow Diagram