---
title: "Generate sound effects"
method: POST
path: "/v1/sound_effect"
tags: ["Start generating"]
---

# Generate sound effects

`POST /v1/sound_effect`

This endpoint will start a new task to generate sound effects from a text description.

## Headers

- `X-Runway-Version` '2024-11-06', required

## Request body

- union
  - object
    - `promptText` string, required — A non-empty text prompt. For text-to-speech, the words to speak. For text-to-audio, a scene description that can include voice direction, dialogue, music, and sound effects.
    - `referenceAudios` union[] — Up to three reference audio clips. When provided, reference them in promptText as @Audio1, @Audio2, and @Audio3 in order.
      - union — A HTTPS URL, Runway or data URI containing an encoded audio. See [our docs](/assets/inputs#audio) on audio inputs for more information.
        - string — A HTTPS URL, Runway upload URI, or base64 data URI (e.g. `data:audio/mp3;base64,...`, up to 16MB) containing an encoded audio. See [our docs](/assets/inputs#audio) on audio inputs for more information.
        - string — A Runway upload URI. See https://docs.dev.runwayml.com/assets/uploads for more information.
        - string — A data URI containing encoded media.
    - `speechRate` integer — Relative speech speed. Negative is slower, positive is faster; 0 is normal.
    - `loudnessRate` integer — Relative output loudness. Negative is quieter, positive is louder; 0 is normal.
    - `pitchRate` integer — Pitch shift in semitones. Negative lowers, positive raises; 0 is unchanged.
    - `sampleRate` 8000 | 16000 | 24000 | 32000 | 44100 | 48000 — Output sample rate in Hz.
    - `outputFormat` 'wav' | 'mp3' | 'ogg_opus' — Output audio container/format.
    - `model` 'seed_audio', required
  - object
    - `promptText` string, required — A text description of the sound effect to generate.
    - `duration` number — The duration of the sound effect in seconds, between 0.5 and 30 seconds. If not provided, the duration will be determined automatically based on the text description.
    - `loop` boolean — Whether the output sound effect should be designed to loop seamlessly.
    - `model` 'eleven_text_to_sound_v2', required

## Response `200`

The task that was created.

- object
  - `id` string, uuid, required — The ID of the task that was created. Use this to retrieve the task later.
  - `estimatedCost` object, required — The maximum credits this task may charge. The final amount may be lower after the task completes.
    - `credits` number, required — Estimated cost of the generation in credits.

## Other responses

- `400` — The request was rejected. Inspect `error` or `issues` (when present) and retry with a corrected request.
- `429` — You have exceeded the rate limit for this endpoint.

## Changes

- **2026-08-07** `73a12c23285c` — 2 info
  - added the non-success response with the status `400`
  - added the required property `estimatedCost` to the response with the `200` status
- **2026-07-06** `8b1c682294d7` — 1 info
  - added `subschema #1: seed_audio` to the request body `oneOf` list
- **2025-12-04** `6dab1bdab5d3` — 2 info
  - the `model` request property default value `eleven_text_to_sound_v2` was removed
  - added the media type `application/json` for the response with the status `429`
- **2025-12-03** `c2a88516fa0c` — 1 info
  - the `model` request property default value `eleven_text_to_sound_v2` was added
- **2025-12-03** `76b3962cf49e` — 1 info
  - the `model` request property default value `eleven_text_to_sound_v2` was removed

[Full history](https://skmtc.dev/runwayml/apis/runwayml-api/changes/v1/sound_effect/post.md)

---

[API](https://skmtc.dev/runwayml/apis/runwayml-api.md) · [All operations](https://skmtc.dev/runwayml/apis/runwayml-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/runwayml/runwayml-api/revisions/efc9e5abc4d0/schema)