---
title: "Add or replace audio"
method: POST
path: "/tools/add_audio"
---

# Add or replace audio

`POST /tools/add_audio`

Mix an audio track over a video, or replace the original. Async — returns 202 with a pending job; poll GET /tool_jobs/{uid} until `status` is `completed` or `failed`.

## Request body

- object
  - `video_url` string, uri, required — Video URL
  - `audio_url` string, uri, required — Audio URL
  - `mode` 'mix' | 'replace', required — Mode
  - `volume` number — 1.0 = original level
  - `loop` 'on' | 'off' — Loop the audio to match the video's length. Turn off for one-shot sounds
  - `ducking` 'off' | 'subtle' | 'medium' | 'heavy' — Dip the new audio when the video's original audio is present. Mix mode only
  - `metadata` string — Arbitrary metadata string stored with the tool run

## Response `202`

Tool run accepted

- object
  - `uid` string
  - `tool` 'add_audio'
  - `status` 'pending' | 'running' | 'completed' | 'failed' — pending → running → completed / failed
  - `progress` integer — 0-100 job progress, 100 once completed
  - `inputs` object — Inputs the job was created with
  - `outputs` object
    - `video_url` string, uri
  - `metadata` string, nullable — Arbitrary metadata string round-tripped from the create request
  - `self` string, uri
  - `created_at` string, date-time
  - `completed_at` string, date-time, nullable
  - `error_message` string, nullable — Human-readable failure reason (only present on failed jobs)

## Other responses

- `402` — API quota exhausted — upgrade required
- `404` — Unknown tool
- `422` — Input validation failure

---

[API](https://skmtc.dev/bannerbear/apis/bannerbear-v5-api.md) · [All operations](https://skmtc.dev/bannerbear/apis/bannerbear-v5-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/bannerbear/bannerbear-v5-api/revisions/6aa425420a10/schema)