---
title: "Pitch-shift or time-stretch the instrumental"
method: POST
path: "/songs/{id}/renders"
tags: ["Songs"]
---

# Pitch-shift or time-stretch the instrumental

`POST /songs/{id}/renders`

## Request

- Base URL: `https://vocaless.app/api/v1`
- URL: `https://vocaless.app/api/v1/songs/{id}/renders`
- Auth: HTTP bearer

Queues a transposed or tempo-adjusted copy of the instrumental, which is what makes it usable as a backing track in a different key. Renders are **free**, they cost only storage. Applies to the instrumental, never the original.

If that exact render already exists the response is `ready` with an empty `job_id` and nothing is queued. Otherwise it is `queued`: poll `GET /songs/{id}/renders` with the same parameters until it returns a URL. Requires `status: "ready"`, and at least one of `semitones`/`speed` must differ from the default.

## Path parameters

- `id` string, uuid, required

## Request body

- object
  - `semitones` integer, required
  - `speed` integer

## Response `202`

Success

- object
  - `job_id` string, required
  - `semitones` number, required
  - `speed` number, required
  - `status` 'queued' | 'ready', required

## Other responses

- `400`: `INVALID_REQUEST` — The request body or query failed validation.
- `401`: `UNAUTHORIZED` — Missing, malformed, or revoked API key.
- `402`: `STORAGE_LIMIT` — The account's storage limit would be exceeded, or storage billing is delinquent.
- `404`: `NOT_FOUND` — No such song, or it belongs to another account.
- `409`: `NOT_READY` — The song has no instrumental yet. Separate it before rendering one.
- `429`: `RATE_LIMITED` — Too many requests for this API key.
- `503`: `STORAGE_UNAVAILABLE` — The storage backend could not be reached. If you use your own bucket, check that it is up, then retry.

---

[API](https://skmtc.dev/vocaless/apis/vocaless-api.md) · [All operations](https://skmtc.dev/vocaless/apis/vocaless-api/llms.txt) · [OpenAPI document](https://skmtc.dev/vocaless/apis/vocaless-api/revisions/db15b6df3aa2?raw)