A Notification System for Reminders is a platform that allows users to schedule alerts and delivers them through various channels (email, SMS, push notifications, or in-app) when due. The system acts as a central hub to manage scheduled events and dispatch notifications to users via their preferred methods. A real-world analogy is the reminder feature in Slack or calendar applications; for instance, Slack relies on scheduled jobs to ensure messages reach users at the precise moment. Here, we generalize that concept to a web-scale service capable of handling millions of concurrent users.