Scale Todo App Software Design Interview

25 Software Design Interview Questions to Crack Any Programming and Technical Interviews

Frequently asked System Design Questions and links to useful resources

Hello guys, If you have given any coding interview then you know that System design or Software design problems are an important part of programming job interviews, and if you want to do well, you must prepare this topic.

In the past, when I shared my list of programming interview questions, I have shared a couple of System design questions but my readers kept asking me for more questions, as it is a hard topic to master, and more and more practice is needed.

I had my own list of questions that I have collected from various interviews with friends and colleagues but I needed more questions for this article when I stumbled upon the Grokking System Design Interview course on Educative.

It's like a godsend resource because it not only gives you a lot of System design question but also provide all the knowledge and tools you need to solve those questions.

In other words, this course teaches you step by step how to proceed with designing a real-world system like Facebook, Twitter, Uber, etc.

Also, there are not too many system design interview courses and resources you can look to prepare this topic. When I was searching I only find Grokking The System Design course by Educative and Preparing for the System Design Interview course on Udemy by Rajat Mehta.

Other than that I didn't find any online course which is completely focused on solving system design problems from top companies like Amazon, Google, Microsoft, Apple, SalesForce, Flipcart, etc.

When you combine this course with this list of questions you will have the best material to prepare for your System design interview. You can also first try all these questions by yourself before joining the course or looking it my solution for some of the questions.

This works best only if you have some Coding experience and fundamental knowledge of Computer Science and Software Design. If you are a complete beginner in this area then I would suggest you first start with a fundamental course to learn basics like Java Programming: Principles of Software Design on Coursera or the Web Application & Software Architecture 101 on The Educative Team itself.

This course will not only teach you how to solve a real-world problem using Java with multiple classes but also software design which is not just coding but also involves logical thinking and design, which is very important for becoming a successful Software Developer.

6. How would you create your own Instagram? (solution)

Instagram is a photo-sharing application that provides some custom filters to enhance your photo quality. Your application should have photo upload functionality, tagging photos for search, and some basic filters. If you could add share or social network that could be great.

Btw, if you stuck, you can see the free solution provided on the Educative Grokking System design course as well.

7. How do you design global file sharing and storage apps like Google Drive or Dropbox?
These are used to store and share files, photos, and other media. How do you go about designing things like allowing users to upload/view/search/share files or photos? track permissions for file sharing, and allow multiple users to edit the same document?

If you like Youtube video, here is a nice one which will teach you how to design a Dropbox or Google Drive or any other document hosting solution:

8. How do you design a chat application like WhatsApp or Facebook Messenger?

You have surely used WhatsApp and Facebook, right? No? If not let me tell you that a chat application allows you to send messages to your friend. It's a point to point connection.

You keep a friend list and see their status and chat with them. In WhatsApp, you can also connect groups but that is for advanced and experienced developers. At a minimum, you should provide a design to keep a friend list and send and receive messages from them.

If you need some tips then I suggest you check out Preparing for the System Design Interview Course on Udemy, where you will find a whole case study to solve this problem.

9. How do you design a Twitter Clone?
Twitter is a popular messaging service that lets you broadcast your messages to all your followers. You tweet and your followers see those messages, they can like or retweet.

Make sure you implement common features like followers, hashtag, tweet, delete, etc. If you going nowhere and stuck, you can follow the solution on System Design Interviews: Grokking the System Design Interview.

10. How to design a global video streaming service like YouTube or NetFlix?
While designing a video streaming service like NetFlix or YouTube key thing is smooth streaming and buffering and functioning over low bandwidth connection, how do you manage those challenges. You can check out this system design course to learn how to deal with such problems.

11. How to design an ATM machine?
An ATM machine allows a user to deposit and withdraw cash. It also allows a user to see his balance. How do you design such a system? What are your main challenges?

12. How do you design an API Rate Limiter?

13. How do you design Twitter Search?

14. How to design a Web Crawler like Google?
A Web Crawler goes to a website and crawl all link and index them e.g. Google so that they can later appear in a search result. A Crawler can also use for searching a particular file in a set of directories, how do you design such things? What are the main challenges?

15. How to design Facebook's Newsfeed? What kind of Algorithm will you use?
The newsfeed is an important part of Facebook which allows a user to see what's happening around his world which includes friends and families, the pages he has liked, the group he has followed, and of-course the Facebook Ads.

The job of the Newsfeed algorithm is to show messages which are most important for the user and which can generate high engagement. Obviously, messages from friends and family should take priority.

If you feel not going anywhere and stuck, you can follow the solution on System Design Interviews: Grokking the System Design Interview.

16. How to design Yelp or Nearby Friends?

17. How to design a global ride-hailing service e.g. Uber, Grab, or Ola backend?
Uber and Ola are two of the most popular ride-hailing services, it brings both drivers and passengers together. How do you go about designing to allow a passenger to see nearby taxis and book them?

18. How to design BookMyShow?
A website that allows you to book cinema and event tickets. This is actually an Indian startup that is doing well.

19. How to design a social network + message board service sites like Quora, Reddit, or HackerNews?

Reddit, Quora, and HackerNews are some of the most popular social network sites where users can post questions or share links. Other users can answer questions or comment on the shared links.

20. How do you design an application like Airbnb?

It allows some users to upload rooms for rent and other users to rent them. Some of the features are only available to admins, publishers, and subscribers.

21. How do you design an Elevator of the Lift system?
We All know about Elevators and Lift as most of us use it. You might have seen them in pairs and in some big office buildings you can see 3 to 4 lifts. You need to design software for that so that it can reach use quickly on different levels. You can assume you have two lifts and a 10-floor building.

Here is a nice Youtube video which explains the solution to this popular system design interview question, you can watch it right here.

22. How would you go about designing an e-commerce website like Amazon or Flipcart at scale?

23. How would you go about designing the e-commerce website using microservices, how will you handle transactions?

24. How would you design a Parking Lot system? (solved)
This is an interesting problem and asked for companies like Amazon, Google, Apple, and other FAANG companies.

You should cover the following use cases

Give a user ticket when he enters
Generate price when the user exits.

Here is a nice youtube video that explains this problem and the solution. They also discuss APIs, Database models, and database choice. they also discuss on how to make it distributed. We also discuss concurrency.

24. Create an autocomplete feature like word suggestions on search engines? Scale it to millions of users?

25. How would you go about creating a feed posting on a social network like Facebook, Instagram, Twitter, LinkedIn, etc?

If you need some guidance then I suggest you check out Preparing for the System Design Interview Course on Udemy, where Rajat Mehta has a whole case study to solve this problem. You will also learn about high-level design, low-level design, and Database design in this masterpiece.

That's all about some of the frequently asked System Design Interview Questions for Java Programmers. Btw, these questions are not just useful for Java Programmers but also for Python, C++, Java, and Ruby Programmers. These questions are actually independent of programming language and test your software design and architecture skill.

7 Resources to Crack System Design Interviews

If you need some more resources like online courses and guides and a few more questions to practice then you can check out these online courses and book to further sharpen your knowledge and crack any System design interviews.

Preparing for the System Design Interview
Java Programming: Principles of Software Design
Cracking the Code Interview — 189 Problems with Solutions
Software Engineer Interview Unleashed by Udemy
The System Design Primer on Github
Web Application & Software Architecture 101
Grokking System Design Interview

Other Java Design Patterns tutorials you may like

My favorite courses to learn Software Architecture (courses)
5 Free Courses to learn Object Oriented Programming (courses)
Difference between Factory and Dependency Injection Pattern? (answer)
Top 5 Courses to learn Microservices in Java with Spring (courses)
How to create thread-safe Singleton in Java? (example)
How to implement the Strategy Design Pattern in Java? (example)
Difference between Factory and AbstractFactory Pattern? (example)
18 Java Design Pattern Interview Questions with Answers (list)
Difference between State and Strategy Design Pattern in Java? (answer)
Top 5 Courses to learn Design Patterns in Java (courses)
5 Free Courses to learn Data Structure and Algorithms (courses)
Top 5 Courses to learn Software Design and Architecture (dev.to)

Thanks for reading this article so far. If you like these design pattern interview questions then please share with your friends and colleagues. If you have any questions or feedback then please drop a note.

P.S.- If you are looking for some free courses to learn Design Pattern and Software Architecture, I also suggest you check out the Java Design Patterns and Architecture course by John Purcell on Udemy. It's completely free, all you need to do is create an Udemy account to access this course.