Generate Runway sound effects

POST

runwayml

sound_effect

curl https://api.cometapi.com/runwayml/v1/sound_effect \
  --request POST \
  --header "Authorization: Bearer $COMETAPI_KEY" \
  --header "Content-Type: application/json" \
  --data '{
  "model": "eleven_text_to_sound_v2",
  "promptText": "Gentle rain falling on a wooden roof with distant thunder.",
  "duration": 5,
  "loop": true
}'

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

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

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

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

Choose a model

Model ID	Required inputs	Optional controls
`eleven_text_to_sound_v2`	`promptText` with 1–3000 characters	`duration` in whole seconds from 1 to 30; `loop`
`seed_audio`	`promptText` with 1–2048 characters	Up to three `referenceAudios`; speech, loudness, and pitch controls; output format

For eleven_text_to_sound_v2, omit duration to choose the length from the prompt. Set loop: true to request a repeating sound effect. For seed_audio, refer to referenceAudios in the prompt as @Audio1, @Audio2, and @Audio3, in array order. Omit referenceAudios when you do not need a reference. Replace each example audio URL with an accessible HTTPS URL of your audio file. Do not include duration, loop, or voice with this model on this endpoint.

Configure audio controls

Field	Values	Meaning
`speechRate`	Integer from -50 to 100	Negative slows speech; positive speeds it up.
`loudnessRate`	Integer from -50 to 100	Negative reduces volume; positive increases it.
`pitchRate`	Integer from -12 to 12	Pitch shift in semitones.
`sampleRate`	`8000`, `16000`, `24000`, `32000`, `44100`, `48000`	Audio sample rate in Hz.
`outputFormat`	`wav`, `mp3`, `ogg_opus`	Output audio format.

For the three rate controls, omit the field or use 0 to keep its normal value.

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_text_to_sound_v2
seed_audio

Request settings for eleven_text_to_sound_v2.

model

enum<string>

required

Model ID for this request.

Available options:

eleven_text_to_sound_v2

Allowed value: "eleven_text_to_sound_v2"

promptText

string

required

A text description of the sound effect to generate.

Required string length: 1 - 3000

duration

integer

Sound effect duration in whole seconds, from 1 to 30. Omit this field to choose duration from the prompt.

Required range: 1 <= x <= 30

loop

boolean

default:false

Set true to request a sound effect that loops seamlessly. Defaults to false.

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/sound_effect \
  --request POST \
  --header "Authorization: Bearer $COMETAPI_KEY" \
  --header "Content-Type: application/json" \
  --data '{
  "model": "eleven_text_to_sound_v2",
  "promptText": "Gentle rain falling on a wooden roof with distant thunder.",
  "duration": 5,
  "loop": true
}'

{
  "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

Configure audio controls

Retrieve the result

Authorizations

Body

Response

​Choose a model

​Configure audio controls

​Retrieve the result

Authorizations

Body

Response

Choose a model

Configure audio controls

Retrieve the result