Mastering Notifications: The Top Interview Questions and Answers

Notifications are an integral part of modern applications. Those small popups and alerts keep users informed of new messages, events, and activities happening within an app. As a developer, you need a solid grasp of notifications to build engaging user experiences.

In this guide, we’ll cover the most common notifications interview questions and equip you with sample answers to ace your next job interview.

Why Notifications Matter

Let’s first understand why notifications are so important:

  • Engagement: Notifications let users know about new content or activities, which makes them want to come back to your app. This boosts engagement and retention.

  • Timely information – By pushing timely updates to users, notifications keep your app content fresh and prevent it from going stale

  • Advantage over others: Apps that use notifications well usually have an upper hand over others. Users like being informed of relevant happenings in real-time.

  • Main interaction point – For some apps, notifications serve as the primary touchpoint with users. Handling them right is critical.

Now let’s dive into the top notification interview questions and answers:

Q1. What are the main types of notifications on Android?

Android has two main notification types:

  • Status bar notifications – These appear as icons in the status bar with a brief description. Tapping them opens the full notification interface.

  • Heads-up notifications – More urgent notifications that pop up as full-screen alerts when the device is in use. They demand immediate user attention.

Q2. How are notifications handled differently on iOS and Android?

There are some key differences in how iOS and Android handle notifications:

  • Grouping – iOS allows grouping by app or thread. Android has notification channels instead.

  • Management – iOS settings are more centralized. Android settings are per app.

  • Display – iOS shows notification info on lock screen. Android requires unlocking to view details.

  • Action buttons – iOS supports action buttons within notifications. Limited capability in Android.

  • Expiration – iOS notifications don’t expire. Android allows setting expiration time.

Q3. What are notification channels in Android and why are they useful?

Notification channels categorize notifications by topic or type. Users can control each channel’s visibility and behavior.

Benefits include:

  • Giving users more control over notifications

  • Preventing notification overload by adjusting per channel

  • Allowing users to mute specific channels

  • Customizing sounds, visibility for each channel

Q4. How would you implement a simple notification in an Android app?

Here are the basic steps:

  1. Create a notification channel for API 26+ devices

  2. Build a NotificationCompat.Builder object with title, text, icon etc.

  3. Call NotificationManagerCompat’s notify() and pass the notification ID and builder object

  4. Launch activity when notification is tapped using PendingIntent

This displays the notification. Customizations like actions can be added.

Q5. What are some best practices for push notifications?

Some best practices include:

  • Send notifications with useful, personalized content

  • Avoid overdoing promotions or spamming users

  • Let users control frequency and channel subscriptions

  • Localize notifications for different regions

  • Keep notifications succinct but clear

  • Test different notification styles for engagement

  • Analyze metrics like CTR, opt-outs to refine strategy

Q6. How would you troubleshoot notifications not being delivered?

I would troubleshoot this issue as follows:

  • Check if notifications are being triggered from backend by inspecting logs

  • Verify client device is receiving notification payload and not blocking it

  • Test network connectivity between client and server

  • Inspect notification code for any errors or missed requirements

  • Debug issues with third party push notification services if used

  • Evaluate payload size, frequency to see if limits are being crossed

Q7. What are some advantages of using FCM for push notifications?

Firebase Cloud Messaging has several advantages:

  • Fully integrated with Firebase with detailed analytics

  • Free service up to a generous limit

  • Support for downstream and upstream messaging

  • Options for topic-based notifications

  • Payload targeting based on audience segments

  • Reliable and fast message delivery

  • Handles client app lifecycle changes

Q8. How can you make notifications accessible to users with disabilities?

Some ways to improve accessibility include:

  • Providing textual alternatives for icons and images

  • Ensuring color contrast meets minimum ratios

  • Making notifications screen reader friendly

  • Allowing text enlargement without loss of content

  • Adding visual alerts and vibrations for hearing impaired

  • Allowing voice commands where possible

  • Avoiding dependency on interaction like swipe gestures

Q9. What are some unique ways you have used notifications in your apps?

In one app, I used notifications for:

  • Welcome messages on signup encouraging exploration

  • Milestone celebrations on profile completion

  • Nudges to invite friends with referral benefits

  • Profile views and reactions to foster engagement

  • Polls to crowdsource opinions from users

The key was crafting notifications that brought value instead of annoying users.

Q10. How would you go about improving the performance of a notifications system?

Some performance optimization techniques:

  • Implementing caching and background processing using services

  • Database indexing and optimizing long running queries

  • Using a separate lightweight microservice for notifications

  • Scaling notification servers independently from app servers

  • Load testing and profiling resource usage under heavy load

  • Checking for and eliminating any N+1 queries

  • Setting up monitoring for key metrics like CPU usage, memory, latency

Key Takeaways

  • Notifications increase user engagement and app stickiness when designed thoughtfully.

  • iOS and Android offer different notification behaviors – know the specifics.

  • Channels and customization settings allow granular user control.

  • Focus on valuable content that informs but doesn’t overwhelm users.

  • Diagnose and fix notification delivery issues methodically.

  • Leverage tools like FCM but know their limitations.

  • Optimize notification infrastructure for scalability and performance.

I hope these notification interview questions and sample answers will help you master this topic and land your dream mobile development job. Use them as a reference to strengthen your conceptual knowledge and highlight it confidently during interviews.

notifications interview questions

What experience do you have with iOS development and working with Push Notifications and CloudKit?

In my previous job at XYZ company, I was in charge of making and maintaining the iOS app for the company, which used Push Notifications and CloudKit a lot. I have over 3 years of experience working with iOS frameworks and APIs, including Push Notifications and CloudKit.

  • As part of my job at XYZ company, I set up Push Notifications to let users know about new products, sales, and deals at the right time. This led to a 20% increase in app engagement and a 15% increase in sales.
  • I also used CloudKit to store user data and keep it in sync across devices. This made it easy for our users to access their data on multiple devices, which led to a 25% rise in app retention and a 10% rise in daily active users.
  • I know how to set up and fix problems with Push Notifications using tools like Apple Push Notification Service and Firebase Cloud Messaging. This feature helped us cut down on downtime and quickly fix any problems that came up, which made the app run better and gave users a better overall experience.
  • I’m also very good at programming in Swift and Objective-C, and I know a lot about Apple’s iOS development ecosystem, which includes Xcode, Interface Builder, and Frameworks.
  • Overall, I’m sure that my skills in iOS development, working with Push Notifications, and CloudKit make me a strong candidate for this job. I’m excited to join the company and use my skills to help the team do well.

Can you describe your experience with configuring and managing CloudKit containers?

I had the chance to set up and manage several CloudKit containers for different projects while I was a software engineer at XYZ Company. As an example, I set up a CloudKit container for a real-time chat app that cut message latency by 200%. I was also in charge of a CloudKit container for a fitness tracking app that grew to serve 500,000 users in just six months after it came out.

To manage the CloudKit containers, I used the CloudKit Dashboard to monitor usage and optimize performance. We also worked together to set up automatic backups and disaster recovery plans in case something bad happened.

I also made sure the CloudKit containers were safe by setting up access control and authentication systems that were in line with Apple’s best practices. Because of this, none of the CloudKit containers I was in charge of had any security or data breaches while I was there.

  • Could you give me an example of a CloudKit container that you set up or managed before?
  • How did you make sure that the CloudKit container would work well and be able to grow?
  • What safety measures did you take to make sure the data in the CloudKit container was safe?

I am sure that I can help your company with any problems it may have in this area thanks to my experience setting up and managing CloudKit containers.

Notification Service System Design Interview Question to handle Billions of users & Notifications


Which of these can be used to send notifications in ServiceNow?

There are only two ways to trigger a notification. By record update/insert, or by an event.…

How can sensitive data like contacts or access to the camera or other sensors be secured in the world of mobile apps?

Access to a user’s data or sensors is restricted by a permissions system. That means that when the app wants to use a feature like GPS, it has to ask the user for permission and explain why this permission is necessary. The user can agree, or reject the request.

How does a notification service work?

Let’s call them the publisher since they publish messages. The publishers will send requests to the notification service to send notification messages for them. The client’s request to the notification service will first hit the load balancer. The load balancer helps distribute load evenly across the notification system servers.

What is notification & why is it used?

What is notification and why it is used? Email notifications are used to send users email or notifications about specific activities in system, such as updates to incidents or change requests. How to call email script into notification?

What should a notification system look like?

The system should be able to prioritize notifications. OTPs are high priority messages while news feed updates may be lower priority. The system should be able to support Email, SMS and push notifications on mobile and web browser. It should be an isolated system that is easy to integrate into an existing system, such as Facebook or LinkedIn.

How do you answer a ServiceNow interview question?

To answer this question well, the candidate should have an in-depth knowledge of the company, and this is easily possible by running an online search and going through the company’s website. The interview questions for ServiceNow intend to test the candidate’s experience.

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