In my system user is allowed to set notifications schedule. He can choose any date and time when he wants to get messages. I have discovered one mechanims is named as Celery in Python. That executes tasks asyncronly. Due this I have pair of questions:
What you are looking for is something to process background tasks submitted to a queue from your web server. To that end, Celery is a good option and easy to configure. A more comprehensive list can be found here. None of these options would integrate with a user interface, they would integrate with your web server. They can queue jobs based on what is sent from the client side, which could be included as part of handling the request-response flow.
Also, this article provides a good reference for how to schedule periodic tasks using celery.
