When you submit an image generation task to the 4o Image 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:
  • 4o image generation task completed successfully
  • 4o image 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": "success",
  "data": {
    "taskId": "task12345",
    "info": {
      "result_urls": [
        "https://example.com/result/image1.png"
      ]
    }
  }
}

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Status Code Description

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code
integer
required
Callback status code indicating task processing result:
Status CodeDescription
200Success - Image generation completed successfully
400Bad Request - Image content in filesUrl violates content policy, image size exceeds maximum limit, unable to process provided image file, content flagged by OpenAI as violating policies
451Download Failed - Unable to download image from the provided filesUrl
500Server Error - Please try again later, failed to get user token, failed to generate image, GPT 4O failed to edit the picture
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msg
string
required
Status message providing detailed status description
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data.taskId
string
required
Task ID, consistent with the taskId returned when you submitted the task
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data.info
object
Image generation result information, returned on success
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data.info.result_urls
array
List of generated image URLs, returned on success with accessible download links

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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('/4o-image-callback', (req, res) => {
  const { code, msg, data } = req.body;
  
  console.log('Received 4o image generation callback:', {
    taskId: data.taskId,
    status: code,
    message: msg
  });
  
  if (code === 200) {
    // Task completed successfully
    console.log('4o image generation completed');
    const resultUrls = data.info?.result_urls || [];
    
    console.log(`Generated ${resultUrls.length} images:`);
    resultUrls.forEach((url, index) => {
      console.log(`Image ${index + 1}: ${url}`);
    });
    
    // Process generated images
    // Can download images, save locally, etc.
    
  } else {
    // Task failed
    console.log('4o image generation failed:', msg);
    
    // Handle failure cases...
    if (code === 400) {
      console.log('Content policy violation or parameter error');
    } else if (code === 451) {
      console.log('Image download failed');
    } 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');
});

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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 taskId 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. Image Processing: Image download and processing should be done in asynchronous tasks to avoid blocking callback response

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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
  • Generated image URLs may have time limits, recommend downloading and saving promptly
  • Pay attention to content policy compliance to avoid generation failures due to policy violations

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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 4o image details endpoint to regularly query task status. We recommend querying every 30 seconds.