Music Extension Callbacks

System will call this callback when audio generation is complete

When you submit a music extension task to the Suno API, you can use the callBackUrl parameter to set a callback URL. The system will automatically push the results to your specified address when the task is completed.

Callback Mechanism Overview

INFO

The callback mechanism eliminates the need to poll the API for task status. The system will proactively push task completion results to your server.

Webhook Security

To ensure the authenticity and integrity of callback requests, we strongly recommend implementing webhook signature verification. See our Webhook Verification Guide for detailed implementation steps.

Callback Timing

The system will send callback notifications in the following situations:

Text generation completed (callbackType: "text")
First audio track generation completed (callbackType: "first")
All audio tracks generation completed (callbackType: "complete")
Audio generation task failed
Errors occurred during task processing

Callback Method

HTTP Method: POST
Content Type: application/json
Timeout Setting: 15 seconds

Callback Request Format

When the task progresses or completes, the system will send a POST request to your callBackUrl in the following format:

Complete Success Callback

json

{
  "code": 200,
  "msg": "All generated successfully.",
  "data": {
    "callbackType": "complete",
    "task_id": "2fac****9f72",
    "data": [
      {
        "id": "e231****-****-****-****-****8cadc7dc",
        "audio_url": "https://example.cn/****.mp3",
        "stream_audio_url": "https://example.cn/****",
        "image_url": "https://example.cn/****.jpeg",
        "prompt": "[Verse] Night city lights shining bright",
        "model_name": "chirp-v3-5",
        "title": "Iron Man",
        "tags": "electrifying, rock",
        "createTime": "2025-01-01 00:00:00",
        "duration": 198.44
      },
      {
        "id": "e231****-****-****-****-****8cadc7dc",
        "audio_url": "https://example.cn/****.mp3",
        "stream_audio_url": "https://example.cn/****",
        "image_url": "https://example.cn/****.jpeg",
        "prompt": "[Verse] Night city lights shining bright",
        "model_name": "chirp-v3-5",
        "title": "Iron Man",
        "tags": "electrifying, rock",
        "createTime": "2025-01-01 00:00:00",
        "duration": 228.28
      }
    ]
  }
}

First Track Complete Callback

json

{
  "code": 200,
  "msg": "First track generated successfully.",
  "data": {
    "callbackType": "first",
    "task_id": "2fac****9f72",
    "data": [
      {
        "id": "e231****-****-****-****-****8cadc7dc",
        "audio_url": "https://example.cn/****.mp3",
        "stream_audio_url": "https://example.cn/****",
        "image_url": "https://example.cn/****.jpeg",
        "prompt": "[Verse] Night city lights shining bright",
        "model_name": "chirp-v3-5",
        "title": "Iron Man",
        "tags": "electrifying, rock",
        "createTime": "2025-01-01 00:00:00",
        "duration": 198.44
      }
    ]
  }
}

Text Generation Complete Callback

json

{
  "code": 200,
  "msg": "Text generation completed.",
  "data": {
    "callbackType": "text",
    "task_id": "2fac****9f72",
    "data": []
  }
}

Failure Callback

json

{
  "code": 501,
  "msg": "Audio generation failed.",
  "data": {
    "callbackType": "error",
    "task_id": "2fac****9f72",
    "data": []
  }
}

Status Code Description

code (integer, required)

Callback status code indicating task processing result:

Status Code	Description
200	Success - Request has been processed successfully
400	Validation Error - Lyrics contained copyrighted material
408	Rate Limited - Timeout
413	Conflict - Uploaded audio matches existing work of art
500	Server Error - An unexpected error occurred while processing the request
501	Audio generation failed
531	Server Error - Sorry, the generation failed due to an issue. Your credits have been refunded. Please try again

msg (string, required)

Status message providing detailed status description

data.callbackType (string, required)

Callback type indicating the stage of generation:

text: Text generation complete
first: First track complete
complete: All tracks complete
error: Generation failed

data.task_id (string, required)

Task ID, consistent with the taskId returned when you submitted the task

data.data (array, required)

Array of generated audio tracks. Empty for text callbacks or failures.

data.data[].id (string)

Audio unique identifier (audioId)

data.data[].audio_url (string)

Audio file URL for download

data.data[].stream_audio_url (string)

Streaming audio URL for real-time playback

data.data[].image_url (string)

Cover image URL

data.data[].prompt (string)

Generation prompt/lyrics used

data.data[].model_name (string)

Model name used for generation (e.g., "chirp-v3-5")

data.data[].title (string)

Music title

data.data[].tags (string)

Music tags/genre

data.data[].createTime (string)

Creation timestamp

data.data[].duration (number)

Audio duration in seconds

Callback Reception Examples

Here are example codes for receiving callbacks in popular programming languages:

Node.js

javascript

const express = require('express');
const fs = require('fs');
const https = require('https');
const app = express();

app.use(express.json());

app.post('/suno-extend-callback', (req, res) => {
  const { code, msg, data } = req.body;
  
  console.log('Received Suno music extension callback:', {
    taskId: data.task_id,
    callbackType: data.callbackType,
    status: code,
    message: msg
  });
  
  if (code === 200) {
    // Task progressed or completed successfully
    const { callbackType, task_id, data: tracks } = data;
    
    console.log(`Callback type: ${callbackType}`);
    console.log(`Number of tracks: ${tracks.length}`);
    
    switch (callbackType) {
      case 'text':
        console.log('Text generation completed, waiting for audio...');
        break;
        
      case 'first':
        console.log('First track completed, processing remaining tracks...');
        downloadTracks(tracks, task_id);
        break;
        
      case 'complete':
        console.log('All tracks completed successfully!');
        downloadTracks(tracks, task_id);
        break;
    }
    
  } else {
    // Task failed
    console.log('Suno music extension failed:', msg);
    
    // Handle specific error types
    if (code === 400) {
      console.log('Validation error - check for copyrighted content');
    } else if (code === 408) {
      console.log('Rate limited - please wait before retrying');
    } else if (code === 413) {
      console.log('Content conflict - audio matches existing work');
    } else if (code === 501) {
      console.log('Generation failed - may need to adjust parameters');
    } else if (code === 531) {
      console.log('Server error with credit refund - safe to retry');
    }
  }
  
  // Return 200 status code to confirm callback received
  res.status(200).json({ status: 'received' });
});

// Function to download tracks
function downloadTracks(tracks, taskId) {
  tracks.forEach((track, index) => {
    const { id, audio_url, image_url, title, duration } = track;
    
    console.log(`Track ${index + 1}: ${title} (${duration}s)`);
    
    // Download audio file
    if (audio_url) {
      downloadFile(audio_url, `suno_extend_${taskId}_${id}.mp3`)
        .then(() => console.log(`Audio downloaded: ${id}`))
        .catch(err => console.error(`Audio download failed for ${id}:`, err));
    }
    
    // Download cover image
    if (image_url) {
      downloadFile(image_url, `suno_cover_${taskId}_${id}.jpeg`)
        .then(() => console.log(`Cover downloaded: ${id}`))
        .catch(err => console.error(`Cover download failed for ${id}:`, err));
    }
  });
}

// Helper function to download files
function downloadFile(url, filename) {
  return new Promise((resolve, reject) => {
    const file = fs.createWriteStream(filename);
    
    https.get(url, (response) => {
      if (response.statusCode === 200) {
        response.pipe(file);
        file.on('finish', () => {
          file.close();
          resolve();
        });
      } else {
        reject(new Error(`HTTP ${response.statusCode}`));
      }
    }).on('error', reject);
  });
}

app.listen(3000, () => {
  console.log('Callback server running on port 3000');
});

Python

python

from flask import Flask, request, jsonify
import requests
import os

app = Flask(__name__)

@app.route('/suno-extend-callback', methods=['POST'])
def handle_callback():
    data = request.json
    
    code = data.get('code')
    msg = data.get('msg')
    callback_data = data.get('data', {})
    callback_type = callback_data.get('callbackType')
    task_id = callback_data.get('task_id')
    tracks = callback_data.get('data', [])
    
    print(f"Received Suno music extension callback:")
    print(f"Task ID: {task_id}, Type: {callback_type}")
    print(f"Status: {code}, Message: {msg}")
    
    if code == 200:
        # Task progressed or completed successfully
        print(f"Callback type: {callback_type}")
        print(f"Number of tracks: {len(tracks)}")
        
        if callback_type == 'text':
            print("Text generation completed, waiting for audio...")
        elif callback_type == 'first':
            print("First track completed, processing remaining tracks...")
            download_tracks(tracks, task_id)
        elif callback_type == 'complete':
            print("All tracks completed successfully!")
            download_tracks(tracks, task_id)
            
    else:
        # Task failed
        print(f"Suno music extension failed: {msg}")
        
        # Handle specific error types
        if code == 400:
            print("Validation error - check for copyrighted content")
        elif code == 408:
            print("Rate limited - please wait before retrying")
        elif code == 413:
            print("Content conflict - audio matches existing work")
        elif code == 501:
            print("Generation failed - may need to adjust parameters")
        elif code == 531:
            print("Server error with credit refund - safe to retry")
    
    # Return 200 status code to confirm callback received
    return jsonify({'status': 'received'}), 200

def download_tracks(tracks, task_id):
    """Download audio tracks and cover images"""
    for i, track in enumerate(tracks):
        track_id = track.get('id')
        audio_url = track.get('audio_url')
        image_url = track.get('image_url')
        title = track.get('title')
        duration = track.get('duration')
        
        print(f"Track {i + 1}: {title} ({duration}s)")
        
        # Download audio file
        if audio_url:
            try:
                audio_filename = f"suno_extend_{task_id}_{track_id}.mp3"
                download_file(audio_url, audio_filename)
                print(f"Audio downloaded: {track_id}")
            except Exception as e:
                print(f"Audio download failed for {track_id}: {e}")
        
        # Download cover image
        if image_url:
            try:
                image_filename = f"suno_cover_{task_id}_{track_id}.jpeg"
                download_file(image_url, image_filename)
                print(f"Cover downloaded: {track_id}")
            except Exception as e:
                print(f"Cover download failed for {track_id}: {e}")

def download_file(url, filename):
    """Download file from URL and save locally"""
    response = requests.get(url, stream=True)
    response.raise_for_status()
    
    os.makedirs('downloads', exist_ok=True)
    filepath = os.path.join('downloads', filename)
    
    with open(filepath, 'wb') as f:
        for chunk in response.iter_content(chunk_size=8192):
            f.write(chunk)

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=3000)

PHP

php

<?php
header('Content-Type: application/json');

// Get POST data
$input = file_get_contents('php://input');
$data = json_decode($input, true);

$code = $data['code'] ?? null;
$msg = $data['msg'] ?? '';
$callbackData = $data['data'] ?? [];
$callbackType = $callbackData['callbackType'] ?? '';
$taskId = $callbackData['task_id'] ?? '';
$tracks = $callbackData['data'] ?? [];

error_log("Received Suno music extension callback:");
error_log("Task ID: $taskId, Type: $callbackType");
error_log("Status: $code, Message: $msg");

if ($code === 200) {
    // Task progressed or completed successfully
    error_log("Callback type: $callbackType");
    error_log("Number of tracks: " . count($tracks));
    
    switch ($callbackType) {
        case 'text':
            error_log("Text generation completed, waiting for audio...");
            break;
            
        case 'first':
            error_log("First track completed, processing remaining tracks...");
            downloadTracks($tracks, $taskId);
            break;
            
        case 'complete':
            error_log("All tracks completed successfully!");
            downloadTracks($tracks, $taskId);
            break;
    }
    
} else {
    // Task failed
    error_log("Suno music extension failed: $msg");
    
    // Handle specific error types
    if ($code === 400) {
        error_log("Validation error - check for copyrighted content");
    } elseif ($code === 408) {
        error_log("Rate limited - please wait before retrying");
    } elseif ($code === 413) {
        error_log("Content conflict - audio matches existing work");
    } elseif ($code === 501) {
        error_log("Generation failed - may need to adjust parameters");
    } elseif ($code === 531) {
        error_log("Server error with credit refund - safe to retry");
    }
}

// Return 200 status code to confirm callback received
http_response_code(200);
echo json_encode(['status' => 'received']);

function downloadTracks($tracks, $taskId) {
    foreach ($tracks as $i => $track) {
        $trackId = $track['id'] ?? '';
        $audioUrl = $track['audio_url'] ?? '';
        $imageUrl = $track['image_url'] ?? '';
        $title = $track['title'] ?? '';
        $duration = $track['duration'] ?? 0;
        
        error_log("Track " . ($i + 1) . ": $title ({$duration}s)");
        
        // Download audio file
        if (!empty($audioUrl)) {
            try {
                $audioFilename = "suno_extend_{$taskId}_{$trackId}.mp3";
                downloadFile($audioUrl, $audioFilename);
                error_log("Audio downloaded: $trackId");
            } catch (Exception $e) {
                error_log("Audio download failed for $trackId: " . $e->getMessage());
            }
        }
        
        // Download cover image
        if (!empty($imageUrl)) {
            try {
                $imageFilename = "suno_cover_{$taskId}_{$trackId}.jpeg";
                downloadFile($imageUrl, $imageFilename);
                error_log("Cover downloaded: $trackId");
            } catch (Exception $e) {
                error_log("Cover download failed for $trackId: " . $e->getMessage());
            }
        }
    }
}

function downloadFile($url, $filename) {
    $downloadDir = 'downloads';
    if (!is_dir($downloadDir)) {
        mkdir($downloadDir, 0755, true);
    }
    
    $filepath = $downloadDir . '/' . $filename;
    
    $fileContent = file_get_contents($url);
    if ($fileContent === false) {
        throw new Exception("Failed to download file from URL");
    }
    
    $result = file_put_contents($filepath, $fileContent);
    if ($result === false) {
        throw new Exception("Failed to save file locally");
    }
}
?>

Best Practices

Callback URL Configuration Recommendations

Use HTTPS: Ensure your callback URL uses HTTPS protocol for secure data transmission
Verify Source: Verify the legitimacy of the request source in callback processing
Idempotent Processing: The same task_id may receive multiple callbacks, ensure processing logic is idempotent
Quick Response: Callback processing should return a 200 status code as quickly as possible to avoid timeout
Asynchronous Processing: Complex business logic should be processed asynchronously to avoid blocking callback response
Handle Multiple Callbacks: Be prepared to receive text, first, and complete callbacks for the same task

Important Reminders

Callback URL must be a publicly accessible address
Server must respond within 15 seconds, otherwise it will be considered a timeout
If 3 consecutive retries fail, the system will stop sending callbacks
You may receive multiple callbacks for the same task (text → first → complete)
Please ensure the stability of callback processing logic to avoid callback failures due to exceptions
Handle copyright and conflict errors appropriately (codes 400, 413)
Credit refunds are automatic for certain server errors (code 531)

Troubleshooting

If you do not receive callback notifications, please check the following:

Network Connection Issues

Confirm that the callback URL is accessible from the public network
Check firewall settings to ensure inbound requests are not blocked
Verify that domain name resolution is correct

Server Response Issues

Ensure the server returns HTTP 200 status code within 15 seconds
Check server logs for error messages
Verify that the interface path and HTTP method are correct

Content Format Issues

Confirm that the received POST request body is in JSON format
Check that Content-Type is application/json
Verify that JSON parsing is correct

Audio Processing Issues

Confirm that audio URLs are accessible
Check audio download permissions and network connections
Verify audio save paths and permissions
Handle both regular and streaming audio URLs appropriately
Process multiple tracks in the same callback

Review error messages for copyright violations (code 400)
Check for content conflicts with existing works (code 413)
Ensure compliance with platform content policies
Adjust lyrics or prompts if flagged

Rate Limiting Issues

Handle timeout errors gracefully (code 408)
Implement appropriate retry logic with backoff
Monitor API usage to avoid rate limits
Consider upgrading service plan if needed

Alternative Solution

If you cannot use the callback mechanism, you can also use polling:

Poll Query Results

Use the get music details endpoint to regularly query task status. We recommend querying every 30 seconds.

Music Extension Callbacks ​

Callback Mechanism Overview ​

Callback Timing ​

Callback Method ​

Callback Request Format ​

Status Code Description ​

code (integer, required) ​

msg (string, required) ​

data.callbackType (string, required) ​

data.task_id (string, required) ​

data.data (array, required) ​

data.data[].id (string) ​

data.data[].audio_url (string) ​

data.data[].stream_audio_url (string) ​

data.data[].image_url (string) ​

data.data[].prompt (string) ​

data.data[].model_name (string) ​

data.data[].title (string) ​

data.data[].tags (string) ​

data.data[].createTime (string) ​

data.data[].duration (number) ​

Callback Reception Examples ​

Best Practices ​

Troubleshooting ​

Alternative Solution ​

Music Extension Callbacks

Callback Mechanism Overview

Callback Timing

Callback Method

Callback Request Format

Status Code Description

code (integer, required)

msg (string, required)

data.callbackType (string, required)

data.task_id (string, required)

data.data (array, required)

data.data[].id (string)

data.data[].audio_url (string)

data.data[].stream_audio_url (string)

data.data[].image_url (string)

data.data[].prompt (string)

data.data[].model_name (string)

data.data[].title (string)

data.data[].tags (string)

data.data[].createTime (string)

data.data[].duration (number)

Callback Reception Examples

Best Practices

Troubleshooting

Alternative Solution