Extend Music API

POST

https://udioapi.pro/api/v2/extend

Extend existing music tracks by adding new content to the end.

Quick Start

Core Parameters

origin_task_idrequired

The task ID from your original music generation request. This tells the system which completed generation task contains the audio you want to extend. You can find this ID in the response of your initial generation API call.

extend_audio_indexrequired

Specifies which audio from the original generation to extend. Use 0 for the first audio or 1 for the second audio. Most generation requests return 2 audio variations, so you need to choose which one to extend.

custom_modeoptional

Controls extension behavior. Set to false (or omit) to automatically inherit all original parameters (prompt, style, title, etc.) for seamless continuation. Set to true to override with custom parameters for creative transformation.

1. Simple Extension (Inherit Original Style)

{
  "origin_task_id": "gen20e094aeaaxxxxxxxxxxxxx3bksv",
  "extend_audio_index": 0,
  "custom_mode": false
}

Automatically uses all parameters from the original task - no additional settings needed. Perfect for seamlessly continuing the same musical style.

2. Custom Extension (New Style)

{
  "origin_task_id": "gen20e094aeaaxxxxxxxxxxxxx3bksv",
  "extend_audio_index": 0,
  "custom_mode": true,
  "prompt": "Change the music style to be calm and lyrical.",
  "style": "lyrical",
  "title": "lyrical song",
  "extensionStartTime": 150,
  "tags": "war"
}

Override original parameters with new creative settings. Ideal for transforming the musical direction while extending the track.

Response

{
  "code": 200,
  "message": "success",
  "workId": "ext2e31202d4f629447fa75f603ae2470565bksv"
}

Use the workId with the Feed API to check progress.

Parameters

Required Parameters

origin_task_idrequiredstring

The task_id from your original music generation request.

extend_audio_indexrequirednumber

Which audio to extend: 0 for the first audio, 1 for the second audio.

Optional Parameters

custom_modeoptionalboolean

false (inherit original parameters) or true (use custom parameters). Default: false

callback_urloptionalstring

Webhook URL to receive real-time results. Must be publicly accessible.

Custom Mode Parameters (when custom_mode: true)

promptrequired if custom_modestring

New lyrics or description for the extension.

styleoptionalstring

Musical style/genre for the extension.

titleoptionalstring

Title for the extended track.

extensionStartTimeoptionalnumber

Start time in seconds for the extension. Must be > 0 and < original audio duration.

tagsoptionalstring

Additional tags for the extension.

Code Examples

cURL

Inherit Mode

curl -X POST "https://udioapi.pro/api/v2/extend" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "origin_task_id": "gen20e094aeaadfe494ea33a5c80ee596083bksv",
    "extend_audio_index": 0,
    "custom_mode": false
  }'

Custom Mode

curl -X POST "https://udioapi.pro/api/v2/extend" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "origin_task_id": "gen20e094aeaadfe494ea33a5c80ee596083bksv",
    "extend_audio_index": 0,
    "custom_mode": true,
    "prompt": "Change the music style to be calm and lyrical.",
    "style": "lyrical",
    "title": "lyrical song",
    "extensionStartTime": 150,
    "tags": "war"
  }'

JavaScript

Inherit Mode

const response = await fetch('https://udioapi.pro/api/v2/extend', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    origin_task_id: 'gen20e094aeaadfe494ea33a5c80ee596083bksv',
    extend_audio_index: 0,
    custom_mode: false
  })
});

const data = await response.json();
console.log(data);

Custom Mode

const response = await fetch('https://udioapi.pro/api/v2/extend', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    origin_task_id: 'gen20e094aeaadfe494ea33a5c80ee596083bksv',
    extend_audio_index: 0,
    custom_mode: true,
    prompt: 'Change the music style to be calm and lyrical.',
    style: 'lyrical',
    title: 'lyrical song',
    extensionStartTime: 150,
    tags: 'war'
  })
});

const data = await response.json();
console.log(data);

Python

Inherit Mode

import requests

url = "https://udioapi.pro/api/v2/extend"
headers = {
    "Authorization": "Bearer YOUR_API_KEY",
    "Content-Type": "application/json"
}
data = {
    "origin_task_id": "gen20e094aeaadfe494ea33a5c80ee596083bksv",
    "extend_audio_index": 0,
    "custom_mode": False
}

response = requests.post(url, headers=headers, json=data)
print(response.json())

Custom Mode

import requests

url = "https://udioapi.pro/api/v2/extend"
headers = {
    "Authorization": "Bearer YOUR_API_KEY",
    "Content-Type": "application/json"
}
data = {
    "origin_task_id": "gen20e094aeaadfe494ea33a5c80ee596083bksv",
    "extend_audio_index": 0,
    "custom_mode": True,
    "prompt": "Change the music style to be calm and lyrical.",
    "style": "lyrical",
    "title": "lyrical song",
    "extensionStartTime": 150,
    "tags": "war"
}

response = requests.post(url, headers=headers, json=data)
print(response.json())

Error Responses

400 Bad Request

{
  "code": 400,
  "message": "Please specify which audio to extend. Add \"extend_audio_index\" to your request, using 0 for the first audio or 1 for the second."
}

400 Invalid Task

{
  "code": 400,
  "message": "The provided \"origin_task_id\" is invalid or could not be found. Please ensure it corresponds to a successfully completed task associated with your API key."
}

400 Audio Not Ready

{
  "code": 400,
  "message": "The requested audio is not yet completed. Please wait for the task to complete and try again."
}