Extend

Python

import requests

url = "https://api.musicgpt.com/api/public/v1/extend"
headers = {"Authorization": "<API_KEY>"}
data = {
  "extend_after": 35.0,
  "prompt": "Add a calming piano outro",
  "lyrics": "Let the journey fade away",
  "gender": "neutral", 
  "lyrics_section_to_extend": "New_lyrics",
  "num_outputs": 1,
  "title": "My Generated Track",
  "webhook_url": "https://example.com/webhook"
}

# Option 1: audio_url
data["audio_url"] = "<YOUR_AUDIO_URL>"
response = requests.post(url, headers=headers, data=data)

# Option 2: File Upload
# with open("song.mp3", "rb") as f:
#     files = {"audio_file": f}
#     response = requests.post(url, headers=headers, data=data, files=files)
print(response.json())

curl --request POST \
  --url https://api.musicgpt.com/api/public/v1/extend \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: multipart/form-data' \
  --form audio_url=https://mybucket.s3.amazonaws.com/song.mp3 \
  --form extend_after=35 \
  --form 'audio_file=<string>' \
  --form 'prompt=Add a calming piano outro' \
  --form 'lyrics=Let the journey fade away' \
  --form 'lyrics_section_to_extend=<string>' \
  --form gender=neutral \
  --form 'title=<string>' \
  --form num_outputs=123 \
  --form generate_album_cover=false \
  --form webhook_url=https://example.com/webhook \
  --form 0.audio_file='@example-file' \
  --form 1.audio_file='@example-file'

const form = new FormData();
form.append('audio_url', 'https://mybucket.s3.amazonaws.com/song.mp3');
form.append('extend_after', '35');
form.append('audio_file', '<string>');
form.append('prompt', 'Add a calming piano outro');
form.append('lyrics', 'Let the journey fade away');
form.append('lyrics_section_to_extend', '<string>');
form.append('gender', 'neutral');
form.append('title', '<string>');
form.append('num_outputs', '123');
form.append('generate_album_cover', 'false');
form.append('webhook_url', 'https://example.com/webhook');
form.append('0.audio_file', '{
  "fileName": "example-file"
}');
form.append('1.audio_file', '{
  "fileName": "example-file"
}');

const options = {method: 'POST', headers: {Authorization: '<api-key>'}};

options.body = form;

fetch('https://api.musicgpt.com/api/public/v1/extend', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.musicgpt.com/api/public/v1/extend",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_url\"\r\n\r\nhttps://mybucket.s3.amazonaws.com/song.mp3\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"extend_after\"\r\n\r\n35\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_file\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"prompt\"\r\n\r\nAdd a calming piano outro\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics\"\r\n\r\nLet the journey fade away\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics_section_to_extend\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"gender\"\r\n\r\nneutral\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"title\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"num_outputs\"\r\n\r\n123\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"generate_album_cover\"\r\n\r\nfalse\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"webhook_url\"\r\n\r\nhttps://example.com/webhook\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"0.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"1.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001--",
  CURLOPT_HTTPHEADER => [
    "Authorization: <api-key>",
    "Content-Type: multipart/form-data; boundary=---011000010111000001101001"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.musicgpt.com/api/public/v1/extend"

	payload := strings.NewReader("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_url\"\r\n\r\nhttps://mybucket.s3.amazonaws.com/song.mp3\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"extend_after\"\r\n\r\n35\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_file\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"prompt\"\r\n\r\nAdd a calming piano outro\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics\"\r\n\r\nLet the journey fade away\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics_section_to_extend\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"gender\"\r\n\r\nneutral\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"title\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"num_outputs\"\r\n\r\n123\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"generate_album_cover\"\r\n\r\nfalse\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"webhook_url\"\r\n\r\nhttps://example.com/webhook\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"0.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"1.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001--")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "<api-key>")
	req.Header.Add("Content-Type", "multipart/form-data; boundary=---011000010111000001101001")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.musicgpt.com/api/public/v1/extend")
  .header("Authorization", "<api-key>")
  .header("Content-Type", "multipart/form-data; boundary=---011000010111000001101001")
  .body("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_url\"\r\n\r\nhttps://mybucket.s3.amazonaws.com/song.mp3\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"extend_after\"\r\n\r\n35\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_file\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"prompt\"\r\n\r\nAdd a calming piano outro\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics\"\r\n\r\nLet the journey fade away\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics_section_to_extend\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"gender\"\r\n\r\nneutral\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"title\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"num_outputs\"\r\n\r\n123\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"generate_album_cover\"\r\n\r\nfalse\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"webhook_url\"\r\n\r\nhttps://example.com/webhook\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"0.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"1.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001--")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.musicgpt.com/api/public/v1/extend")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = '<api-key>'
request["Content-Type"] = 'multipart/form-data; boundary=---011000010111000001101001'
request.body = "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_url\"\r\n\r\nhttps://mybucket.s3.amazonaws.com/song.mp3\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"extend_after\"\r\n\r\n35\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_file\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"prompt\"\r\n\r\nAdd a calming piano outro\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics\"\r\n\r\nLet the journey fade away\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics_section_to_extend\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"gender\"\r\n\r\nneutral\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"title\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"num_outputs\"\r\n\r\n123\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"generate_album_cover\"\r\n\r\nfalse\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"webhook_url\"\r\n\r\nhttps://example.com/webhook\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"0.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"1.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001--"

response = http.request(request)
puts response.read_body

{
  "success": true,
  "message": "Extend request submitted successfully",
  "task_id": "task-extend-789",
  "conversion_id_1": "extend-a1b2",
  "conversion_id_2": "extend-c3d4",
  "eta": 38,
  "credit_estimate": 42
}

{
  "success": false,
  "error": "audio_file or audio_url and extend_after are required."
}

{
  "success": false,
  "error": "Internal Server Error"
}

POST

extend

Python

import requests

url = "https://api.musicgpt.com/api/public/v1/extend"
headers = {"Authorization": "<API_KEY>"}
data = {
  "extend_after": 35.0,
  "prompt": "Add a calming piano outro",
  "lyrics": "Let the journey fade away",
  "gender": "neutral", 
  "lyrics_section_to_extend": "New_lyrics",
  "num_outputs": 1,
  "title": "My Generated Track",
  "webhook_url": "https://example.com/webhook"
}

# Option 1: audio_url
data["audio_url"] = "<YOUR_AUDIO_URL>"
response = requests.post(url, headers=headers, data=data)

# Option 2: File Upload
# with open("song.mp3", "rb") as f:
#     files = {"audio_file": f}
#     response = requests.post(url, headers=headers, data=data, files=files)
print(response.json())

curl --request POST \
  --url https://api.musicgpt.com/api/public/v1/extend \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: multipart/form-data' \
  --form audio_url=https://mybucket.s3.amazonaws.com/song.mp3 \
  --form extend_after=35 \
  --form 'audio_file=<string>' \
  --form 'prompt=Add a calming piano outro' \
  --form 'lyrics=Let the journey fade away' \
  --form 'lyrics_section_to_extend=<string>' \
  --form gender=neutral \
  --form 'title=<string>' \
  --form num_outputs=123 \
  --form generate_album_cover=false \
  --form webhook_url=https://example.com/webhook \
  --form 0.audio_file='@example-file' \
  --form 1.audio_file='@example-file'

const form = new FormData();
form.append('audio_url', 'https://mybucket.s3.amazonaws.com/song.mp3');
form.append('extend_after', '35');
form.append('audio_file', '<string>');
form.append('prompt', 'Add a calming piano outro');
form.append('lyrics', 'Let the journey fade away');
form.append('lyrics_section_to_extend', '<string>');
form.append('gender', 'neutral');
form.append('title', '<string>');
form.append('num_outputs', '123');
form.append('generate_album_cover', 'false');
form.append('webhook_url', 'https://example.com/webhook');
form.append('0.audio_file', '{
  "fileName": "example-file"
}');
form.append('1.audio_file', '{
  "fileName": "example-file"
}');

const options = {method: 'POST', headers: {Authorization: '<api-key>'}};

options.body = form;

fetch('https://api.musicgpt.com/api/public/v1/extend', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.musicgpt.com/api/public/v1/extend",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_url\"\r\n\r\nhttps://mybucket.s3.amazonaws.com/song.mp3\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"extend_after\"\r\n\r\n35\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_file\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"prompt\"\r\n\r\nAdd a calming piano outro\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics\"\r\n\r\nLet the journey fade away\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics_section_to_extend\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"gender\"\r\n\r\nneutral\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"title\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"num_outputs\"\r\n\r\n123\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"generate_album_cover\"\r\n\r\nfalse\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"webhook_url\"\r\n\r\nhttps://example.com/webhook\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"0.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"1.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001--",
  CURLOPT_HTTPHEADER => [
    "Authorization: <api-key>",
    "Content-Type: multipart/form-data; boundary=---011000010111000001101001"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.musicgpt.com/api/public/v1/extend"

	payload := strings.NewReader("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_url\"\r\n\r\nhttps://mybucket.s3.amazonaws.com/song.mp3\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"extend_after\"\r\n\r\n35\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_file\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"prompt\"\r\n\r\nAdd a calming piano outro\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics\"\r\n\r\nLet the journey fade away\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics_section_to_extend\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"gender\"\r\n\r\nneutral\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"title\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"num_outputs\"\r\n\r\n123\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"generate_album_cover\"\r\n\r\nfalse\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"webhook_url\"\r\n\r\nhttps://example.com/webhook\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"0.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"1.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001--")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "<api-key>")
	req.Header.Add("Content-Type", "multipart/form-data; boundary=---011000010111000001101001")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.musicgpt.com/api/public/v1/extend")
  .header("Authorization", "<api-key>")
  .header("Content-Type", "multipart/form-data; boundary=---011000010111000001101001")
  .body("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_url\"\r\n\r\nhttps://mybucket.s3.amazonaws.com/song.mp3\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"extend_after\"\r\n\r\n35\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_file\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"prompt\"\r\n\r\nAdd a calming piano outro\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics\"\r\n\r\nLet the journey fade away\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics_section_to_extend\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"gender\"\r\n\r\nneutral\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"title\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"num_outputs\"\r\n\r\n123\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"generate_album_cover\"\r\n\r\nfalse\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"webhook_url\"\r\n\r\nhttps://example.com/webhook\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"0.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"1.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001--")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.musicgpt.com/api/public/v1/extend")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = '<api-key>'
request["Content-Type"] = 'multipart/form-data; boundary=---011000010111000001101001'
request.body = "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_url\"\r\n\r\nhttps://mybucket.s3.amazonaws.com/song.mp3\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"extend_after\"\r\n\r\n35\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"audio_file\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"prompt\"\r\n\r\nAdd a calming piano outro\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics\"\r\n\r\nLet the journey fade away\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"lyrics_section_to_extend\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"gender\"\r\n\r\nneutral\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"title\"\r\n\r\n<string>\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"num_outputs\"\r\n\r\n123\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"generate_album_cover\"\r\n\r\nfalse\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"webhook_url\"\r\n\r\nhttps://example.com/webhook\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"0.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"1.audio_file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n{\r\n  \"fileName\": \"example-file\"\r\n}\r\n-----011000010111000001101001--"

response = http.request(request)
puts response.read_body

{
  "success": true,
  "message": "Extend request submitted successfully",
  "task_id": "task-extend-789",
  "conversion_id_1": "extend-a1b2",
  "conversion_id_2": "extend-c3d4",
  "eta": 38,
  "credit_estimate": 42
}

{
  "success": false,
  "error": "audio_file or audio_url and extend_after are required."
}

{
  "success": false,
  "error": "Internal Server Error"
}

Extend an existing audio file by generating new content after a specific timestamp.

Endpoint

POST /v1/extend

This endpoint allows users to extend an existing audio file or stream by appending new audio content after a specific timestamp. The new content is generated using a prompt and optional lyrics.

Request Parameters

Parameter	Type	Required	Description
`audio_file`	`UploadFile`	Optional	Upload the audio file to extend. Required if `audio_url` is not provided.
`audio_url`	`String`	Optional	Public or S3 URL to the input audio. Required if `audio_file` is not provided.
`extend_after`	`Float`	Required	Time (in seconds) after which new audio is generated.
`prompt`	`String`	Optional	Describes the desired extension sound. Example: “Add a melodic flute section”
`title`	`String`	Optional	Title of the generated music
`lyrics`	`String`	Optional	Original lyrics of song. Max 2000 characters.
`lyrics_section_to_extend`	`String`	Optional	Optional lyrics for the extended segment. Max 3000 characters.
`gender`	`String`	Optional	Voice style if vocals are generated. Must be one of `male`, `female`, `neutral`.
`num_outputs`	`int`	Optional	The number of outputs to generate (1 or 2 only, default : 2).
`webhook_url`	`String`	Optional	Callback URL for async result delivery.

💡 Note: You must provide either audio_file or audio_url — at least one is required.

content-type: multipart/form-data

Sample Output

Listen to the extended audio. Prompt: loud drums sound - audio input : Rose and Bruno Mars - APT extend after: 6

Download Audio

Try it Yourself

Visit the Extend Endpoint Explorer to play around — set your payload, hit send, and listen to the generated results live.

Sample Request

cURL

curl -X POST "https://api.musicgpt.com/api/public/v1/extend" \
-H "accept: application/json" \
-H "Authorization: <api_key>" \
-F "audio_file=@/path/to/audio.mp3" \
-F "extend_after=35.0" \
-F "prompt=Add a calming piano outro" \
-F "lyrics=Let the journey fade away" \
-F "gender=neutral" \
-F "webhook_url=https://example.com/webhook"

Python

import requests

url = "https://api.musicgpt.com/api/public/v1/extend"
headers = {"Authorization": "<API_KEY>"}
data = {
  "prompt": "Add a calming piano outro",
  "lyrics": "Let the journey fade away",
  "extend_after": 35.0,
  "gender": "neutral",
  "webhook_url": "https://example.com/webhook"
}

# Option 1: audio_url
files = {}
data["audio_url"] = "https://lalals.s3.amazonaws.com/audio/example.mp3"
response = requests.post(url, headers=headers, data=data, files=files)

# Option 2: File Upload
# with open("audio.mp3", "rb") as f:
#     files = {"audio_file": f}
#     response = requests.post(url, headers=headers, data=data, files=files)

# print(response.json())

🔐 Replace {path_to_your_audio_file}, api_key, and webhook_url before executing.

Sample Response

Success (200 OK)

{
  "success": true,
  "message": "Extend request submitted successfully",
  "task_id": "task-extend-789",
  "conversion_id_1": "extend-a1b2",
  "conversion_id_2": "extend-c3d4",
  "eta": 38,
  "credit_estimate": 42
}

Webhook Response

When the extension process completes, the webhook receives:

{
  "success": true,
  "conversion_type": "Extend",
  "task_id": "task-extend-789",
  "conversion_id": "extend-a1b2",
  "conversion_path": "https://lalals.s3.amazonaws.com/conversions/extend-a1b2.mp3",
  "conversion_path_wav": "https://lalals.s3.amazonaws.com/conversions/extend-a1b2.wav",
  "conversion_duration": 192.12,
  "is_flagged": false,
  "reason": "",
  "lyrics": "Let the journey fade away",
  "lyrics_timestamped": [],
  "title": "Outro Symphony"
}

Webhook Delivery

Once the generation is complete, webhooks will be triggered to deliver the following:

Standard Requests (non-instrumental):

2 (webhooks) x Extend conversion details (one per version)
2 (webhooks) x Lyrics with timestamp data
1 Album Cover Image

Webhook responses include detailed metadata including task_id, conversion_id, audio files (conversion_path), lyrics etc.

Common Errors

422 Unprocessable Entity: Missing required fields like extend_after, or neither audio_file nor audio_url provided.
500 Internal Server Error: An unexpected error occurred during processing.

The response provides a downloadable or streamable extended audio file.

Authorizations

Authorization

string

header

required

Body

multipart/form-data

Option 1
Option 2

audio_url

string

required

Input audio URL (supported format: YouTube URL).

Example:

"https://mybucket.s3.amazonaws.com/song.mp3"

extend_after

number<float>

required

Time in seconds after which to start the extension.

Example:

35

audio_file

file

Uploaded audio file to be extended.

prompt

string

Describes how the extended section should sound.

Example:

"Add a calming piano outro"

lyrics

string

Original lyrics of song

Maximum string length: 2000

Example:

"Let the journey fade away"

lyrics_section_to_extend

string

Lyrics to be used for the extended portion(optional, max 3000 characters).

Maximum string length: 3000

gender

enum<string>

Voice style if vocal content is generated.

Available options:

male,

female,

neutral

Example:

"neutral"

title

string

Title of the generated music track

num_outputs

number<integer>

The number of outputs to generate (1 or 2 only):default is 2.

generate_album_cover

boolean

default:false

Whether to generate an album cover for the generated audio

webhook_url

string

Callback URL for async processing results.

Example:

"https://example.com/webhook"

Response

Successfully initiated extend task

success

boolean

message

string

task_id

string

conversion_id_1

string

conversion_id_2

string

eta

integer

Estimated processing time in seconds

credit_estimate

number<float>

API Documentation

Utilities

Resources

Keep in mind

Features

Sample Request Endpoints

Helper Endpoints

Conversion Endpoints

Endpoint

Request Parameters

Sample Output

Try it Yourself

Sample Request

cURL

Python

Sample Response

Success (200 OK)

Webhook Response

Webhook Delivery

Standard Requests (non-instrumental):

Common Errors

Authorizations

Body

Response

​Endpoint

​Request Parameters

​Sample Output

​Try it Yourself

​Sample Request

​cURL

​Python

​Sample Response

​Success (200 OK)

​Webhook Response

​Webhook Delivery

​Standard Requests (non-instrumental):

​Common Errors

Authorizations

Body

Response

Endpoint

Request Parameters

Sample Output

Try it Yourself

Sample Request

cURL

Python

Sample Response

Success (200 OK)

Webhook Response

Webhook Delivery

Standard Requests (non-instrumental):

Common Errors