Notification system design in HLD - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to identify the main component responsible for sending notifications.

HLD

The component that handles sending notifications to users is called the [1].

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ACache Server

BUser Database

CLoad Balancer

DNotification Dispatcher

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing the dispatcher with the user database.

Choosing load balancer as it handles traffic but not notifications.

The Notification Dispatcher is the main component that sends notifications to users.

2fill in blank

medium

Complete the code to specify the type of database best suited for storing user notification preferences.

HLD

For storing user notification preferences, a [1] database is preferred because it handles flexible data well.

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ARelational

BNoSQL

CIn-memory

DTime-series

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing relational databases which require fixed schemas.

Selecting in-memory databases which are volatile.

NoSQL databases are good for flexible and scalable storage of user preferences.

3fill in blank

hard

Fix the error in the notification delivery flow by completing the missing step.

HLD

User sends a request → [1] → Notification Queue → Notification Dispatcher → User device

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ANotification Generator

BDatabase

CCache Server

DLoad Balancer

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing Load Balancer which routes traffic but does not generate notifications.

Selecting Database which stores data but does not create notifications.

The Notification Generator creates the notification message before it is queued for delivery.

4fill in blank

hard

Fill both blanks to complete the code for a scalable notification system architecture.

HLD

Use a [1] to distribute incoming requests and a [2] to handle message storage and retries.

Drag options to blanks, or click blank then click option'

ALoad Balancer

BNotification Queue

CCache Server

DUser Database

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up cache server with queue for message handling.

Using user database for message retries.

A Load Balancer distributes requests evenly, and a Notification Queue manages message storage and retries.

5fill in blank

hard

Fill all three blanks to complete the code for a notification system that supports multiple channels.

HLD

Notifications are sent via [1], [2], and [3] to reach users on different devices.

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AEmail

BSMS

CPush Notification

DFTP

Attempts:

3 left

💡 Hint

Common Mistakes

Including FTP which is not used for notifications.

Missing push notifications which are common on mobile devices.

Email, SMS, and Push Notification are common channels used to deliver notifications to users.