Flask and Celery are two popular Python libraries that can be used together to build web apps requiring background task processing. Flask is a lightweight web framework for Python, while Celery is a distributed task queue that allows background tasks to run asynchronously. To use Flask with Celery, take the following steps: 1. Install Flask and Celery using pip. Run the following command: pip install Flask Celery 2. Define the Flask application by creating a Flask app called app.py and define the task to run in the background using Celery. from flask import Flask from celery import Celery app = Flask(__name__) app.config['CELERY_BROKER_URL'] = 'redis://localhost:6379/0' app.config['CELERY_RESULT_BACKEND'] = 'redis://localhost:6379/0' celery = Celery(app.name, broker=app.config['CELERY_BROKER_URL']) celery.conf.update(app.config) @celery.task def long_running_task():     # your long running task code here     pass @app.route('/start_task') def start_task():     long_running_task.delay()     return 'Task started' 3. Run the Celery worker in a separate terminal window using the following command: celery -A app.celery worker --loglevel=info 4. Start the Flask app and serve the web page by running the following command: python app.py 5. Finally, start the task by navigating to https://localhost:5000/start_task in a web browser. This will start the long_running_task function as a background task in Celery. Learn about ActiveBatch’s advanced script management for Python, Javascript, and more.