Design a notification system in HLD - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the primary purpose of a notification system in software architecture?

To deliver timely messages or alerts to users or systems, ensuring they receive important information or updates.

beginner

Name two common types of notifications in system design.

Push notifications (sent to devices in real-time) and email notifications (sent via email servers).

intermediate

Why is scalability important in a notification system?

Because the system must handle increasing numbers of users and messages without delays or failures.

intermediate

What role does a message queue play in a notification system?

It helps manage and buffer notification messages to ensure reliable delivery and handle traffic spikes smoothly.

advanced

Explain the concept of 'fan-out' in the context of notification systems.

Fan-out means sending one notification message to many recipients efficiently, like broadcasting an alert to all users.

Which component is typically responsible for storing user preferences in a notification system?

A User database

B Message queue

C Notification sender

D Load balancer

User database stores user data including notification preferences.

What is the main benefit of using a message queue in notification delivery?

A Improves UI design

B Buffers messages to handle load spikes

C Stores user passwords

D Encrypts notifications

Message queues buffer messages to handle traffic spikes and ensure reliable delivery.

Which notification type is best for instant alerts on mobile devices?

A Push notification

B Email notification

C SMS notification

D In-app notification

Push notifications deliver real-time alerts directly to mobile devices.

What does 'fan-out' mean in notification systems?

A Storing messages in a database

B Encrypting messages

C Deleting old notifications

D Sending one message to many recipients

Fan-out refers to broadcasting one message to multiple users efficiently.

Which of the following is NOT a common challenge in designing notification systems?

A Handling high volume of messages

B Ensuring message delivery

C Designing user interface colors

D Managing user preferences

UI colors are not a core challenge in notification system design.

Describe the key components of a scalable notification system and their roles.

Think about how messages flow from creation to delivery.

Explain how a notification system handles a sudden spike in message volume without losing messages.

Consider how the system manages overload and ensures reliability.