When you submit a lyrics generation 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.

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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.

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Callback Timing

The system will send callback notifications in the following situations:
  • Lyrics generation task completed successfully
  • Lyrics generation task failed
  • Errors occurred during task processing

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Callback Method

  • HTTP Method: POST
  • Content Type: application/json
  • Timeout Setting: 15 seconds
  • Retry Mechanism: Retry 3 times after failure, with intervals of 1 minute, 5 minutes, and 15 minutes respectively

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Callback Request Format

When the task is completed, the system will send a POST request to your callBackUrl in the following format: 
{
  "code": 200,
  "msg": "All generated successfully.",
  "data": {
    "callbackType": "complete",
    "task_id": "3b66882fde0a5d398bd269cab6d9542b",
    "data": [
      {
        "error_message": "",
        "status": "complete",
        "text": "[Verse]\nMoonlight spreads across the windowsill\nStars dance, never standing still\nNight breeze weaves dreams with gentle skill\nLeaving all worries on the hill\n\n[Verse 2]\nLights reflect in your bright eyes\nLike meteors across the skies\nThe world stops in that moment's prize\nChasing future, no goodbyes\n\n[Chorus]\nIn starry dreams we find tomorrow\nBreak free from ordinary sorrow\nAll our dreams will bloom and follow\nDon't fear the path, don't fear tomorrow",
        "title": "Starry Night Dreams"
      }
    ]
  }
}

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Status Code Description

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code
integer
required
Callback status code indicating task processing result:
Status CodeDescription
200Success - Request has been processed successfully
400Please try rephrasing with more specific details or using a different approach
500Internal Error - Please try again later
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msg
string
required
Status message providing detailed status description
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data.callbackType
string
required
Callback type, fixed as complete
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data.task_id
string
required
Task ID, consistent with the task_id returned when you submitted the task
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data.data
array
required
Generated lyrics list
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data.data[].text
string
Lyrics content, returns complete lyrics text on success
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data.data[].title
string
Lyrics title
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data.data[].status
string
required
Generation status:
  • complete - Generation successful
  • failed - Generation failed
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data.data[].error_message
string
Error message, valid when status is failed

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Callback Reception Examples

Here are example codes for receiving callbacks in popular programming languages: 
const express = require('express');
const app = express();

app.use(express.json());

app.post('/suno-lyrics-callback', (req, res) => {
  const { code, msg, data } = req.body;
  
  console.log('Received lyrics callback:', {
    taskId: data.task_id,
    status: code,
    message: msg,
    callbackType: data.callbackType
  });
  
  if (code === 200) {
    // Task completed successfully
    console.log('Lyrics generation completed:', data.data);
    
    // Process generated lyrics data
    data.data.forEach(lyrics => {
      if (lyrics.status === 'complete') {
        console.log(`Lyrics title: ${lyrics.title}`);
        console.log(`Lyrics content: ${lyrics.text}`);
      } else if (lyrics.status === 'failed') {
        console.log(`Lyrics generation failed: ${lyrics.error_message}`);
      }
    });
    
  } else {
    // Task failed
    console.log('Task failed:', msg);
    
    // Handle failure cases...
  }
  
  // Return 200 status code to confirm callback received
  res.status(200).json({ status: 'received' });
});

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

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Best Practices

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Callback URL Configuration Recommendations

  1. Use HTTPS: Ensure your callback URL uses HTTPS protocol for secure data transmission
  2. Verify Source: Verify the legitimacy of the request source in callback processing
  3. Idempotent Processing: The same task_id may receive multiple callbacks, ensure processing logic is idempotent
  4. Quick Response: Callback processing should return a 200 status code as quickly as possible to avoid timeout
  5. Asynchronous Processing: Complex business logic should be processed asynchronously to avoid blocking callback response
  6. Status Checking: Check the status field of each lyrics item to distinguish between success and failure cases

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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
  • Please ensure the stability of callback processing logic to avoid callback failures due to exceptions
  • Pay attention to handling lyrics generation failure cases, check the error_message field for specific error information

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Troubleshooting

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

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Alternative Solution

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

Poll Query Results

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