When you submit a task to the music generation API, you can use the callBackUrl parameter to set a callback URL. When the task is completed, the system will automatically push the results to your specified address.
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.
Callback Timing
The system will send callback notifications in the following situations:
Text generation completed (text stage)
First music track generated (first stage)
All music tracks generated (complete stage)
Music generation task failed
Error occurred during task processing
Callback Method
HTTP Method : POST
Content Type : application/json
Timeout : 15 seconds
When the task is completed, the system will send a POST request to your callBackUrl in the following format:
Text Generation Complete Callback
First Track Complete Callback
All Tracks Complete Callback
Failed Callback
{
"code" : 200 ,
"msg" : "Text generation completed successfully." ,
"data" : {
"callbackType" : "text" ,
"task_id" : "2fac****9f72" ,
"data" : []
}
}
Status Code Description
Callback status code indicating task processing result: Status Code Description 200 Success - Music generation completed 400 Bad Request - Parameter error or content violation 401 Unauthorized - Invalid API key 413 Content Too Long - Prompt or style description exceeds limit 429 Insufficient Credits - Account credit balance insufficient 500 Server Error - Please retry later
Status message providing detailed status description
Callback type indicating the current callback stage:
text: Text generation completed
first: First music track generated
complete: All music tracks generated
failed: Task failed
Task ID, consistent with the taskId returned when you submitted the task
Music generation result information, returned on success
Audio unique identifier (audioId)
data.data[].source_audio_url
Original audio file download link
data.data[].stream_audio_url
Streaming audio playback link
Prompt/lyrics used for generation
Callback Reception Examples
Here are example codes for receiving callbacks in various popular programming languages:
const express = require ( 'express' );
const app = express ();
app . use ( express . json ());
app . post ( '/music-callback' , ( req , res ) => {
const { code , msg , data } = req . body ;
console . log ( 'Received music generation callback:' , {
taskId: data . task_id ,
callbackType: data . callbackType ,
status: code ,
message: msg
});
if ( code === 200 ) {
// Task successful
const { callbackType , data : musicData } = data ;
switch ( callbackType ) {
case 'text' :
console . log ( 'Text generation completed' );
break ;
case 'first' :
console . log ( 'First music track generated' );
if ( musicData . length > 0 ) {
console . log ( `Music title: ${ musicData [ 0 ]. title } ` );
console . log ( `Audio link: ${ musicData [ 0 ]. audio_url } ` );
console . log ( `Duration: ${ musicData [ 0 ]. duration } seconds` );
}
break ;
case 'complete' :
console . log ( 'All music tracks generated' );
console . log ( `Total ${ musicData . length } tracks generated:` );
musicData . forEach (( track , index ) => {
console . log ( `Track ${ index + 1 } : ${ track . title } - ${ track . audio_url } ` );
});
// Process generated music
// Can download music, save locally, etc.
break ;
}
} else {
// Task failed
console . log ( 'Music generation failed:' , msg );
// Handle failure cases...
if ( code === 400 ) {
console . log ( 'Parameter error or content violation' );
} else if ( code === 429 ) {
console . log ( 'Insufficient credits' );
} else if ( code === 500 ) {
console . log ( 'Server internal error' );
}
}
// 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' );
});
from flask import Flask, request, jsonify
import requests
app = Flask( __name__ )
@app.route ( '/music-callback' , methods = [ 'POST' ])
def handle_callback ():
data = request.json
code = data.get( 'code' )
msg = data.get( 'msg' )
callback_data = data.get( 'data' , {})
task_id = callback_data.get( 'task_id' )
callback_type = callback_data.get( 'callbackType' )
music_data = callback_data.get( 'data' , [])
print ( f "Received music generation callback: { task_id } , Type: { callback_type } , Status: { code } " )
if code == 200 :
# Task successful
if callback_type == 'text' :
print ( "Text generation completed" )
elif callback_type == 'first' :
print ( "First music track generated" )
if music_data:
track = music_data[ 0 ]
print ( f "Music title: { track.get( 'title' ) } " )
print ( f "Audio link: { track.get( 'audio_url' ) } " )
print ( f "Duration: { track.get( 'duration' ) } seconds" )
elif callback_type == 'complete' :
print ( "All music tracks generated" )
print ( f "Total { len (music_data) } tracks generated:" )
for i, track in enumerate (music_data):
print ( f "Track { i + 1 } : { track.get( 'title' ) } - { track.get( 'audio_url' ) } " )
# Download music example
try :
audio_url = track.get( 'audio_url' )
if audio_url:
response = requests.get(audio_url)
if response.status_code == 200 :
filename = f "music_ { task_id } _ { i + 1 } .mp3"
with open (filename, "wb" ) as f:
f.write(response.content)
print ( f "Music saved as { filename } " )
except Exception as e:
print ( f "Music download failed: { e } " )
else :
# Task failed
print ( f "Music generation failed: { msg } " )
# Handle failure cases...
if code == 400 :
print ( "Parameter error or content violation" )
elif code == 429 :
print ( "Insufficient credits" )
elif code == 500 :
print ( "Server internal error" )
# Return 200 status code to confirm callback received
return jsonify({ 'status' : 'received' }), 200
if __name__ == '__main__' :
app.run( host = '0.0.0.0' , port = 3000 )
<? 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' ] ?? [];
$taskId = $callbackData [ 'task_id' ] ?? '' ;
$callbackType = $callbackData [ 'callbackType' ] ?? '' ;
$musicData = $callbackData [ 'data' ] ?? [];
error_log ( "Received music generation callback: $taskId , Type: $callbackType , Status: $code " );
if ( $code === 200 ) {
// Task successful
switch ( $callbackType ) {
case 'text' :
error_log ( "Text generation completed" );
break ;
case 'first' :
error_log ( "First music track generated" );
if ( ! empty ( $musicData )) {
$track = $musicData [ 0 ];
error_log ( "Music title: " . ( $track [ 'title' ] ?? '' ));
error_log ( "Audio link: " . ( $track [ 'audio_url' ] ?? '' ));
error_log ( "Duration: " . ( $track [ 'duration' ] ?? 0 ) . " seconds" );
}
break ;
case 'complete' :
error_log ( "All music tracks generated" );
error_log ( "Total " . count ( $musicData ) . " tracks generated:" );
foreach ( $musicData as $index => $track ) {
$title = $track [ 'title' ] ?? '' ;
$audioUrl = $track [ 'audio_url' ] ?? '' ;
error_log ( "Track " . ( $index + 1 ) . ": $title - $audioUrl " );
// Download music example
try {
if ( $audioUrl ) {
$audioContent = file_get_contents ( $audioUrl );
if ( $audioContent !== false ) {
$filename = "music_{ $taskId }_" . ( $index + 1 ) . ".mp3" ;
file_put_contents ( $filename , $audioContent );
error_log ( "Music saved as $filename " );
}
}
} catch ( Exception $e ) {
error_log ( "Music download failed: " . $e -> getMessage ());
}
}
break ;
}
} else {
// Task failed
error_log ( "Music generation failed: $msg " );
// Handle failure cases...
if ( $code === 400 ) {
error_log ( "Parameter error or content violation" );
} elseif ( $code === 429 ) {
error_log ( "Insufficient credits" );
} elseif ( $code === 500 ) {
error_log ( "Server internal error" );
}
}
// Return 200 status code to confirm callback received
http_response_code ( 200 );
echo json_encode ([ 'status' => 'received' ]);
?>
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 : Ensure processing logic is idempotent as the same taskId may receive multiple callbacks
Quick Response : Callback processing should return 200 status code quickly to avoid timeout
Asynchronous Processing : Complex business logic should be processed asynchronously to avoid blocking callback response
Stage-based Processing : Handle different callback stages (text, first, complete) with appropriate business logic
Music Download : Music download and processing should be done in asynchronous tasks to avoid blocking callback response
Important Reminders
Callback URL must be publicly accessible
Server must respond within 15 seconds, otherwise considered timeout
After 3 consecutive retry failures, the system will stop sending callbacks
Ensure stability of callback processing logic to avoid callback failures due to exceptions
Generated audio URLs may have time limits, recommend downloading and saving promptly
Pay attention to content compliance to avoid generation failures due to violations
Music generation has three stages, each stage will trigger callback notifications
Troubleshooting
If you don’t receive callback notifications, please check the following:
Network Connection Issues
Confirm that the callback URL is accessible from the public internet
Check firewall settings to ensure inbound requests are not blocked
Verify that domain name resolution is correct
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
Confirm that the received POST request body is in JSON format
Check if Content-Type is application/json
Verify that JSON parsing is correct
Confirm that audio URLs are accessible
Check music download permissions and network connectivity
Verify music save path and permissions
Note that music content must comply with content policies
Callback Stage Processing
Understand the differences and handling methods of the three callback stages
text stage: Only indicates text generation completed, no audio data
first stage: First music completed, contains data for one track
complete stage: All music completed, contains complete music list
Alternative Solutions
If you cannot use the callback mechanism, you can also use polling:
Poll Query Results Use the Get Music Generation Details interface to regularly query task status. Recommend querying every 30 seconds.