Generate Runway speech from text

POST

runwayml

text_to_speech

curl https://api.cometapi.com/runwayml/v1/text_to_speech \
  --request POST \
  --header "Authorization: Bearer $COMETAPI_KEY" \
  --header "Content-Type: application/json" \
  --data '{
  "model": "eleven_multilingual_v2",
  "promptText": "Welcome to our audio guide. Let us begin the tour.",
  "voice": {
    "type": "runway-preset",
    "presetId": "Maya"
  }
}'

{
  "id": "123e4567-e89b-42d3-a456-426614174000"
}

{
  "code": "<string>",
  "message": "<string>",
  "data": "<unknown>"
}

{
  "error": {
    "message": "<string>",
    "type": "<string>",
    "code": "<string>"
  }
}

Use POST /runwayml/v1/text_to_speech to create a speech task from text. Send your CometAPI API key with Bearer authentication and a JSON request body.

Choose a model and voice

Every request requires model, promptText, and voice.

Model ID	Text limit	Voice configuration
`eleven_multilingual_v2`	1000 UTF-16 code units	`type: runway-preset` and a `presetId`, such as `Maya`
`eleven_v3`	5000 characters	`type: runway-preset` and a `presetId`, such as `Maya`
`seed_audio`	2048 characters	`type: reference-audio` and an `audioUri`

For preset voices, select a presetId from the request schema. For seed_audio, replace the example audioUri with an accessible HTTPS URL of your voice reference. Do not omit voice or send null for this field.

Adjust speech expression

With eleven_v3, promptText can include expressive tags such as [whispers] or [laughs]. The model also accepts these controls:

Field	Values	Meaning
`stability`	Number from 0 to 1	Lower nonzero values allow more expression; higher values are steadier.
`similarityBoost`	Number from 0 to 1	Higher values follow the selected voice more closely.
`style`	Number from 0 to 1	Higher values emphasize the voice style.
`speed`	Number from 0.7 to 1.2	`1` uses normal speed.
`useSpeakerBoost`	`true`	Request greater similarity to the selected voice.
`languageCode`	ISO 639-1 language code	Guide pronunciation and text normalization.
`applyTextNormalization`	`auto`, `on`, `off`	Control how text such as numbers becomes spoken words.
`seed`	Integer from 1 to 4294967295	Set the sampling seed.

For stability, similarityBoost, and style, a value of 0 uses the model default, as does omitting the field. useSpeakerBoost: false also uses the model default. To set a sampling seed, use a positive integer; seed: 0 chooses a seed automatically.

Adjust speech speed and format

With seed_audio, use speechRate and loudnessRate from -50 to 100, or pitchRate from -12 to 12 semitones. These controls accept integers; omission or 0 keeps the normal value. Set sampleRate to 8000, 16000, 24000, 32000, 44100, or 48000 Hz. Set outputFormat to wav, mp3, or ogg_opus. Do not include duration, referenceAudios, or Eleven v3 controls with seed_audio on this endpoint.

Retrieve the result

Save the returned id, then use Get a Runway task to retrieve task status. When status is SUCCEEDED, read the audio URLs in output. If the task fails, inspect failure and failureCode.

Authorizations

Authorization

string

header

required

Use your CometAPI API key.

Body

application/json

eleven_multilingual_v2
eleven_v3
seed_audio

Request settings for eleven_multilingual_v2.

model

enum<string>

required

Model ID for this request.

Available options:

eleven_multilingual_v2

Allowed value: "eleven_multilingual_v2"

promptText

string

required

Text to speak, from 1 to 1000 UTF-16 code units.

Required string length: 1 - 1000

voice

RunwayPresetVoice · object

required

The voice to use for the generated speech.

Show child attributes

Response

Task created. Save the returned id to retrieve task status.

string

required

Task ID for GET /runwayml/v1/tasks/{id}.

status

string

Task state, when returned.

createdAt

string<date-time>

Task submission timestamp, when returned.

output

string<uri>[]

Result URLs, when returned.

failure

string

Failure explanation, when returned.

failureCode

string

Machine-readable failure code, when returned.

estimatedCost

object

Task estimate metadata, when returned.

Show child attributes

cost

object

Task cost metadata, when returned.

Show child attributes

Last modified on September 21, 2026

curl https://api.cometapi.com/runwayml/v1/text_to_speech \
  --request POST \
  --header "Authorization: Bearer $COMETAPI_KEY" \
  --header "Content-Type: application/json" \
  --data '{
  "model": "eleven_multilingual_v2",
  "promptText": "Welcome to our audio guide. Let us begin the tour.",
  "voice": {
    "type": "runway-preset",
    "presetId": "Maya"
  }
}'

{
  "id": "123e4567-e89b-42d3-a456-426614174000"
}

{
  "code": "<string>",
  "message": "<string>",
  "data": "<unknown>"
}

{
  "error": {
    "message": "<string>",
    "type": "<string>",
    "code": "<string>"
  }
}

Content moderation

API keys

Choose a model and voice

Adjust speech expression

Adjust speech speed and format

Retrieve the result

Authorizations

Body

Response

​Choose a model and voice

​Adjust speech expression

​Adjust speech speed and format

​Retrieve the result

Authorizations

Body

Response

Choose a model and voice

Adjust speech expression

Adjust speech speed and format

Retrieve the result