POST
/
api
/
v1
/
generate
/
extend
Extend Music
curl --request POST \
  --url https://api.sunoapi.org/api/v1/generate/extend \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "defaultParamFlag": true,
  "audioId": "5c79****be8e",
  "prompt": "Extend the music with more relaxing notes",
  "style": "Classical",
  "title": "Peaceful Piano Extended",
  "continueAt": 60,
  "model": "V3_5",
  "negativeTags": "Relaxing Piano",
  "callBackUrl": "https://api.example.com/callback"
}'
{
  "code": 200,
  "msg": "success",
  "data": {
    "taskId": "5c79****be8e"
  }
}

​
Parameter Usage Guide

  • When defaultParamFlag is true (Custom Parameters):
    • prompt, style, title and continueAt are required
    • prompt length limit: 3000 characters
    • style length limit: 200 characters
    • title length limit: 80 characters
  • When defaultParamFlag is false (Use Default Parameters):
    • Only audioId is required
    • Other parameters will use the original audio’s parameters

​
Developer Notes

  1. Generated files are retained for 15 days
  2. Model version must be consistent with the source music
  3. This feature is ideal for creating longer compositions by extending existing tracks

Authorizations

​
Authorization
string
header
required

🔑 API Authentication

All endpoints require authentication using Bearer Token.

Get API Key

  1. Visit the API Key Management Page to obtain your API Key

Usage

Add to request headers:

Authorization: Bearer YOUR_API_KEY

⚠️ Note:

  • Keep your API Key secure and do not share it with others
  • If you suspect your API Key has been compromised, reset it immediately from the management page

Body

application/json

Response

200
application/json

Request successful

The response is of type object.