Asynchronously uploading and processing multiple files using webhooks


  • Data Layer concepts of Konfuzio: Project, Document

  • Understanding of API

  • Basic knowledge of web servers and how they handle incoming requests

  • Basic understanding of asynchronous programming concepts, including threads and event handling

  • Familiarity with ngrok and its setup process to expose a local server to the internet

  • Basic knowledge of HTTP protocols, particularly POST requests and JSON payloads

  • Comfortable navigating and executing commands in a terminal or command prompt

Difficulty: Hard

Goal: This tutorial aims to guide users in efficiently uploading a large number of files to Konfuzio by utilizing the Document.from_file (see docs) method in asynchronous mode. The primary objectives achieved through this tutorial are:

  • Efficient File Upload

  • Real-time Notifications

  • Seamless Integration with ngrok

  • Automated Update of Files


You need to install the Konfuzio SDK before diving into the tutorial.
To get up and running quickly, you can use our Colab Quick Start notebook.
Open In Colab

As an alternative you can follow the installation section to install and initialize the Konfuzio SDK locally or on an environment of your choice.


Uploading a large number of files to Konfuzio can be made highly convenient by employing the Document.from_file method in asynchronous mode. This approach allows for the simultaneous upload of multiple files without the need to wait for backend processing. However, a drawback of this method is the lack of real-time updates on processing status. This tutorial outlines a solution using a webhook callback URL to receive notifications once processing is complete, allowing for timely access to results.

Preliminary Steps

Install Flask

Install Flask, which we will use to create a simple web server that will receive the callback from the Konfuzio Server. You can do it using pip:

pip install flask

Set up ngrok

Then you will need to set up ngrok. If you already have a public web server able to receive POST calls, you can ignore this step and just use the callback URL to your web server’s callback end point. To set up ngrok, first create an account on the ngrok website. It is free, and you can use your GitHub or Google account.

Once logged into ngrok, follow the simple instructions available at

On linux, all you need to do is:

  • Download ngrok

  • Follow the instructions to add the authentication token

  • Run this in a terminal:

./ngrok http 5000

This should give you the URL you can use as a callback URL. It should look something like “”.

Now that we have ngrok set up, we can see how to use it to pull the results of asynchronously uploaded files.

Retrieving asynchronously uploaded files using a callback URL

Import the necessary modules:

from flask import Flask, request
from import Project, Document
import threading
from werkzeug.serving import run_simple

Initialize the Project:

project = Project(id_=YOUR_PROJECT_ID)

Create a Flask application:

app = Flask(__name__)

Set the callback URL. You will find this callback url in the ngrok console where you ran ./ngrok http 5000. It should look like “”.

callback_url = YOUR_CALLBACK_URL

Initialize data structures to share information between the threads. We will use the main thread to host our Flask application and to receive the callback responses. We will use a separate thread to send the files to the Konfuzio Server. So, we will use the callback_data_dict to store the callback responses. The data_lock will be used to synchronize access to the callback_data_dict between the two threads, so that we can safely access it from both threads.

callback_data_dict = {}
data_lock = threading.Lock()

Now we can create the callback function that will receive the callback responses from the Konfuzio server. We store the callback response in the callback_data_dict and set the callback_received event to notify the thread which is sending the files that the callback response has been received and that the files can be updated with the new OCR information.

@app.route('/', methods=['POST'])
def callback():
    data = request.json
    file_name = data.get('data_file_name')
    with data_lock:
        if file_name is not None and file_name in callback_data_dict:
            callback_data_dict[file_name]['callback_data'] = data
    return '', 200

Next, create the function that will send the files to the Konfuzio Server. We create a Document object for each file and set the sync parameter to False to indicate that we want to upload the files asynchronously. We also set the callback_url parameter to the callback URL we created earlier.

We then start a thread for each Document to wait for the callback response to be received. Once the callback response for a Document has been received, we can update it with the OCR information.

def update_file(document, file_name):
    print(f'Waiting for callback for {document}')
    print(f'Received callback for {document}')
    assert document.ocr_ready

    print(f'Updated {document} information with OCR results')

def send_files(file_names):
    for file_name in file_names:
        with data_lock:
            callback_data_dict[file_name] = {'callback_received': threading.Event(), 'callback_data': None, 'document': None}
        print(f'Sending {file_name} to Konfuzio servers...')
        document = Document.from_file(file_name, project=project, sync=False, callback_url=callback_url)
        with data_lock:
            callback_data_dict[file_name]['document'] = document

    for file_name in callback_data_dict:
        threading.Thread(target=update_file, args=(callback_data_dict[file_name]['document'], file_name,)).start()

Finally, we can start the Flask application and send the files. Add the path to all the files you want to upload.

if __name__=='__main__':
    thread = threading.Thread(target=lambda: run_simple("", 5000, app))
    file_names = ['LIST.pdf', 'OF.jpg', 'FILES.tiff']
    threading.Thread(target=send_files, args=(file_names,)).start()


In this tutorial, we explored a powerful method for efficiently uploading a large number of files to Konfuzio using asynchronous mode and a webhook callback URL. By leveraging the Document.from_file method and ngrok for exposing a local server, we’ve enabled simultaneous file uploads without the need to wait for backend processing. Additionally, the implementation of a callback function ensures real-time notifications, allowing for timely access to results.

By following this tutorial, you’ve gained valuable insights into the seamless integration of Konfuzio with ngrok, optimizing your workflow for Document processing tasks. This approach not only enhances efficiency but also provides a foundation for building robust, automated solutions for Document management and analysis.