Notification systems serve a variety of purposes, such as order placement and shipment, payment reminders, and problem alerts. These systems typically offer support for email, SMS, and push notifications, as well as features like bulk messaging, high availability, low latency, and scalability. Some popular examples of notification systems include Mailchimp for emails, Twilio for SMS, and Google Cloud Messaging for Android devices. Designing an effective notification system requires careful consideration of authentication and authorization to ensure that messages are delivered to the correct recipient. Microservices that are often part of a notification system include Validation, Scheduling, Prioritization, User Selection, and Notification Template. In addition, a Notification Analytics Service is typically required to monitor messages as they move through the system.

For more information on this example, please refer to the following source: https://nayak-saabyasachi.medium.com/design-a-notification-system-c9c47ed5b9af