Audio Upload and Extension Callbacks

System will call this callback when audio generation is completeWhen you submit an audio upload and 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 #

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

First Track Complete Callback

Text Generation Complete Callback

Failure Callback

{
  "code": 200,
  "msg": "All generated successfully.",
  "data": {
    "callbackType": "complete",
    "task_id": "2fac****9f72",
    "data": [\
      {\
        "id": "e231****-****-****-****-****8cadc7dc",\
        "audio_url": "https://example.cn/****.mp3",\
        "source_audio_url": "https://example.cn/****.mp3",\
        "stream_audio_url": "https://example.cn/****",\
        "source_stream_audio_url": "https://example.cn/****",\
        "image_url": "https://example.cn/****.jpeg",\
        "source_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\
      }\
    ]
  }
}

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) #

Extended audio file URL for download

data.data[].source_audio_url (string) #

Original source audio file URL

data.data[].stream_audio_url (string) #

Extended streaming audio URL for real-time playback

data.data[].source_stream_audio_url (string) #

Original source streaming audio URL

data.data[].image_url (string) #

Extended cover image URL

data.data[].source_image_url (string) #

Original source 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

Python

PHP

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 audio 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 audio 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 - uploaded 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,
      source_audio_url,
      image_url,
      source_image_url,
      title,
      duration
    } = track;

    console.log(`Track ${index + 1}: ${title} (${duration}s)`);

    // Download extended audio file
    if (audio_url) {
      downloadFile(audio_url, `suno_extended_${taskId}_${id}.mp3`)
        .then(() => console.log(`Extended audio downloaded: ${id}`))
        .catch(err => console.error(`Extended audio download failed for ${id}:`, err));
    }

    // Download source audio file
    if (source_audio_url) {
      downloadFile(source_audio_url, `suno_source_${taskId}_${id}.mp3`)
        .then(() => console.log(`Source audio downloaded: ${id}`))
        .catch(err => console.error(`Source audio download failed for ${id}:`, err));
    }

    // Download extended cover image
    if (image_url) {
      downloadFile(image_url, `suno_extended_cover_${taskId}_${id}.jpeg`)
        .then(() => console.log(`Extended cover downloaded: ${id}`))
        .catch(err => console.error(`Extended cover download failed for ${id}:`, err));
    }

    // Download source cover image
    if (source_image_url) {
      downloadFile(source_image_url, `suno_source_cover_${taskId}_${id}.jpeg`)
        .then(() => console.log(`Source cover downloaded: ${id}`))
        .catch(err => console.error(`Source 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');
});

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

Download Both Versions: Consider downloading both extended and source files for comparison

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)

Be aware of both extended and source file URLs for complete asset management

Generated files will be retained for 14 days

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

Download both extended and source audio files as needed

Review error messages for copyright violations (code 400)

Check for content conflicts with existing works (code 413)

Ensure compliance with platform content policies

Adjust uploaded audio or prompts if flagged

Verify uploaded audio originality and ensure it doesn't exceed 2 minutes

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

Extension-Specific Issues

Ensure uploaded audio does not exceed 2 minutes

Verify continueAt parameter is within valid range (greater than 0 and less than audio duration)

Check model version compatibility with source music

Monitor that extended files are properly differentiated from source files

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.

Audio Upload and 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[].source_audio_url (string) # ​

data.data[].stream_audio_url (string) # ​

data.data[].source_stream_audio_url (string) # ​

data.data[].image_url (string) # ​

data.data[].source_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 # ​