I agree with Alex's comment here and would like to add to it with regards to the behavioral interview. From my three years of interviewing I realized that the behavioral interview is taken for granted by most of the candidates including myself and it does pose a lot of weight. You can literally turn your hire/no-hire result through your behavioral interviews. Your behavioral interview generally gives a lot of indications including these:

- Your way of working. How easy it is to get together with you to solve an issue?
- How do you manage disagreements or conflicts at workplace? It's very important that you do not ruin a relation or it becomes difficult to work with you when conflict/disagreement occur (very important).
- How good is your communication? Do you have a difficult time conveying your thoughts in an appropriate manner?
- Do you think from business point of view? Try to answer questions about your projects or past work experience that showcase your ability to think beyond technical expertise.

Hope this helps!

Mid-Level Software Engineer at Walmart

Rushabh Picha

I agree with Alex's and Rahul's answer and I'd like to share my experience when I started at Amazon as a SDE1 engineer. I was a replacement for a senior engineer and was made to work on a project that he left halfway through. Although I had the design of the project and half of the implementation was already done, I still had to spend lot of time debugging and learning new concepts to understand the project on my own. When I asked my mentor about how feasible it is to work on projects which aren't appropriate for a level you are hired for I was said that if I want to progress to the next level in my career I'd need to demonstrate that I could do the work of the subsequent level for at least six months without much assistance. I'm sure scenarios like these are uncommon but for most companies the expectations are what Alex and Rahul mentioned in their comment.

I did interview for the Android role at a FAANG company recently. Although the interview was for a mid-level role I did try my best to prepare myself for a senior level role. I've added a detailed answer on how to crack a mobile system design interview here: <https://www.jointaro.com/question/NyLoSTCyju0rfywZUPvs/what-are-some-good-resources-for-learning-mobile-system-design/>

Moreover, for a Staff level interview I'm sure you'd need to showcase more qualities apart from the technical expertise like leadership, diversity of your work, etc.

I watched that show before moving to the Silicon Valley and always thought that the show is a complete fiction. Now that I am here I could sense the reality of the show.

You should postpone the interview. Meta recruiters are generally OK with candidates postponing the interview. When I interviewed at Meta I was recommended by my recruiter that even if you are prepared for the interview but on the day of the interview you are not in a mood to interview you should request for a postponement. **They truly want you to succeed.**

For me having a breadth of knowledge helped me to come up with alternative solutions for DS&A and System Design (Android). \
\
For DS&A understanding the in-depth working of each and every data structure and understanding the intuition for every algorithm will make you come up with multiple solution for a problem.\
\
Similarly for System Design, the more you read and the more you know it'll be easy to come up with multiple solutions for a problem\
\
Basically, Knowledge Is Wisdom!

Solving data structure problems pattern wise would be the best bet for you if you want to get a hand on it quickly. Rather than solving ten random problems try to solve 10 problems from the same pattern. In this case, you solve 10 problems without bursting your brain 10 times.\
\
Following are the patterns I'd recommend you doing step wise

- Two pointers
  - 3 sum related problems
- Fast and slow pointer
- Cyclic sort
- Binary Search
- Modified Binary Search
- Sliding Window
- Top K elements (using heap)
- Merge interval
- Greedy technique
- BFS and DFS on trees
- BFS and DFS on graphs
- Union Find

Once you do these problems pattern wise you'd find yourself confident and less nervous before seeing a problem.

You can find some common problems for each pattern here: <https://leetcode.com/discuss/career/448285/List-of-questions-sorted-by-common-patterns>\
\
Thanks!

The best bet to understand a recursive problem would be to debug a recursive problem using a **DEBUGGER** or print statements. I'd recommend using a debugger here as that would give you the working for every line of code.\
\
I can definitely say that the moment I learn recursion I got confident in solving almost half the topics on Leetcode. Here is how I tackle a recursive problem: first look for exit condition or a base condition when you want the recursion to exit and then a recursive condition when you want the function to call itself.

I'd say if you have a domain specific interviews like for Android/iOS or FrontEnd the choice of your language does play a role. For Android the interviewers would expect you to write code in Java and Kotlin. When I interviewed at Expedia I was asked to code in Kotlin as that's the official language for Android development.

I have given two on-sites at Meta and I'd like to share what I learned. Meta's interview process usually includes two technical phone, one system design interview (or two for senior roles), and one behavioral interview. Here are some tips based on my experience:

- During the technical phone screen interviews, keep your introduction short. The interviewers already have your resume, so they want more time for problem-solving.

- The problems they ask might not be super hard, but they often have tricky parts or tricky cases to consider.

- In my interviews, I didn't get any hints for the problems. So, it's up to you to lead the problem process start to finish. Try to provide multiple solutions for the problem and work through the time complexity at the end (very important).

- In the System Design interview, the interviewer explains the question and that was the only time when he talked the most, but then you have to build the system on your own from start to end so I'd say the interviewer spoke for only 5% of the entire interview. They won't give you any hints or help just to understand how far you can take the problem.

I hope this helps. Thanks!

I interviewed for a mid-level Android role but I'm sure senior roles have the same interview rounds just the difficulty may vary. Android engineering interview rounds differs from company to company. Here is what my experience was when I interviewed at a few companies recently:

**Meta:** Data structures and Algorithm, System Design, Behavioral

**DoorDash:** Data structures and Algorithm, App live coding, Android domain level round, System Design, Behavioral

**TikTok:** Data structures and Algorithm, App live coding, System Design, Behavioral

**Verkada:** App live coding, Android domain level, System Design, Behavioral

How did I prepare for each interviews

**Data structures and algorithm**: I've been doing this since four years so it just took me a week's time to revise them all. I have solved around 500 problems on Leetcode but you don't need to be doing these many problems. You can just do the commonly asked problems and company specific problems. Try not to memorize a problem but understanding the concept, pattern and intuition will take you a long way. I studied the following data structures and algorithms.

Data structures: Array, stack, queue, HashMap, Heap, Binary Tree, Graphs

Algorithm: Binary Search, Prefix Sum, Sliding Window, BFS and DFS, Union Find, Backtracking and Two Pointers

Then went over the Neetcode 150 problem list <https://neetcode.io/practice>.

**For every company I also went through their tagged problems on leetcode.**

**Android live coding**: Used the Android studio to practice building sample apps like showing api data in a recycler view, build timer app using Android coroutines and compose, migrate data from one screen to another, etc. Following are the things to take care of to ace this interview:

- Make sure you keep a project open in Android Studio while adding some basic libraries for View Model, Coroutines, DI library, Retrofit or their alternatives based on your preference. This will save you a lot of time during interviews.
- Choosing an architecture and justifying it's use
- Clear communication while you code the app
- Recommend using modern ways of building Android apps.

**Android domain level interview**: This interview comprises questions related to Android specific development. I used this Github repository to prepare for this interview <https://github.com/amitshekhariitbhu/android-interview-questions>

**System Design:**

Following are the resources and guidelines that I used to prepare for Meta Android Design interview

- General guidlines:
  - [**https://github.com/weeeBox/mobile-system-design**](https://github.com/weeeBox/mobile-system-design)
  - [**https://proandroiddev.com/a-simple-framework-for-mobile-system-design-interviews-89f6f4134b84**](https://proandroiddev.com/a-simple-framework-for-mobile-system-design-interviews-89f6f4134b84)
- Mock System Design Interviews: [**https://www.youtube.com/@alementuev**](https://www.youtube.com/@alementuev) The feedback part at the end is enlightening.
- Instagram Android Engineering: [**https://instagram-engineering.com/tagged/android**](https://instagram-engineering.com/tagged/android)
- Uber Android System Design: [**https://www.youtube.com/watch?v=SbXDhAKgWek**](https://www.youtube.com/watch?v=SbXDhAKgWek)
- Modern Android App Architecture (Very important): [**https://developer.android.com/courses/pathways/android-architecture**](https://developer.android.com/courses/pathways/android-architecture)

Here are topic specific links that I found very useful

- Pagination: [**https://nordicapis.com/everything-you-need-to-know-about-api-pagination/**](https://nordicapis.com/everything-you-need-to-know-about-api-pagination/) [**https://uxdesign.cc/why-facebook-says-cursor-pagination-is-the-greatest-d6b98d86b6c0**](https://uxdesign.cc/why-facebook-says-cursor-pagination-is-the-greatest-d6b98d86b6c0)
- Web Sockets: [**https://ably.com/topic/websockets**](https://ably.com/topic/websockets)
- Build for Billions (very important if you are interviewing for a big tech company): [**https://developer.android.com/docs/quality-guidelines/build-for-billions**](https://developer.android.com/docs/quality-guidelines/build-for-billions)
- Memory: [**https://developer.android.com/topic/performance/memory-overview**](https://developer.android.com/topic/performance/memory-overview)

To ace a Mobile System Design interview, these are the topics I recommend studying and finding examples for:

- Networking and communication protocols (REST, WebSockets, Server-Sent Events, Push Notifications, etc.)
- Storage (Relational Database, File storage, Key-value based)
- Data Management (Offline storage, Caching, Pre-fetching data, Persistent/In-memory storage, Services/Work Manager)
- Feature Development (Modularization, Dependency Injection, Testing, Accessibility, Localization)

Try to find pros and cons for the following and come up with why would you go with the one over the other

- MVVM vs MVC vs MVP vs MVI design pattern
- Single Activity vs Multi-Activity architecture pattern
- Different Modularization techniques
- Push-based vs pull-based database synchronization
- In-memory storage vs persistent storage
- XML vs Compose

App scalability topics (Important for apps with billions of users)

- Battery consumption
- Building for different network bandwidth
- Accessibility
- Localization
- App profiling (CPU, Network and Battery profiling)

This is my approach while tacking an Android System Design problem:

- What are we building (Client app, API, BE or both (client plus BE))?
- Whom are we building this for (target users, target market, etc)?
- Functional Requirements
- Non-functional requirements
- Defining the network communication protocol on how the app would get data and then defining the APIs
- Defining the app architecture
- Deep diving in any of the feature
- Scalability
- Privacy and Security

**Mindset that help me build an end to end system**: Thinking as if I am using the app and coming up with different scenarios and then discussing possible solution like

- What happens when the user goes on an airplane mode?
- What happens when the user removes the app from the background and then starts it again?
- What happens when the user uninstalls the app and re-installs it?
- What happens when a call or an alarm interrupts the app?

**Behavioral Interview**: I kept ready multiple work-related stories from my past work experiences and did few mock interviews to answer questions in STAR (Situation Task Action Result) format. I used the guidelines from the educative behavioral course.\
Hope this helps. Thank you!

I'd recommend this easy-to-read book to understand how to build an app at scale, written by an Uber Engineer: 'Building Mobile Apps at Scale' <https://www.amazon.com/Building-Mobile-Apps-Scale-Engineering/dp/1638778868>.

Unfortunately, I couldn't find any detailed System Design course for Android, but I could share some resources that I found here and there and compiled them together:

- General guidlines:
  - <https://github.com/weeeBox/mobile-system-design>
  - <https://proandroiddev.com/a-simple-framework-for-mobile-system-design-interviews-89f6f4134b84>
- Mock System Design Interviews: <https://www.youtube.com/@alementuev> The feedback part at the end is enlightening.
- Instagram Android Engineering: <https://instagram-engineering.com/tagged/android>
- Uber Android System Design: <https://www.youtube.com/watch?v=SbXDhAKgWek>
- Modern Android App Architecture (very important): <https://developer.android.com/courses/pathways/android-architecture>

Here are topic specific links that I found very useful

- Pagination: <https://nordicapis.com/everything-you-need-to-know-about-api-pagination/> <https://uxdesign.cc/why-facebook-says-cursor-pagination-is-the-greatest-d6b98d86b6c0>
- Web Sockets: <https://ably.com/topic/websockets>
- Build for Billions (very important if you are interviewing for a big tech company): <https://developer.android.com/docs/quality-guidelines/build-for-billions>
- Memory: <https://developer.android.com/topic/performance/memory-overview>

To ace any Mobile System Design interview, these are the topics I recommend studying and finding examples for:

- Networking and communication protocols (REST, WebSockets, Server-Sent Events, Push Notifications, etc.)
- Storage (Relational Database, Key-based, Shared Preferences)
- Data Management (Offline storage, Caching, Pre-fetching data, Persistent/In-memory storage, Services/Work Manager)
- Feature Development (Modularization, Dependency Injection, Testing, Accessibility)
- Image caching (very important if you are interviewing at companies like Meta, TikTok and Snapchat)
- Privacy and Security

Try to find pros and cons for the following and come up with why would you go with the one over the other

- MVVM vs MVC vs MVP vs MVI design pattern
- Single Activity vs Multi-Activity architecture pattern
- Different app modularization techniques
- Push-based vs pull-based database synchronization
- In-memory storage vs persistent storage
- XML vs Compose

App scalability topics (Important for apps with billions of users)

- Battery consumption
- Building for different network bandwidth
- Accessibility
- Localization
- App profiling (CPU, Network and Battery profiling)

This is my approach while tacking an Android System Design problem:

- What are we building (Client app, ApI, BE or both (client plus BE))
- Whom are we building this for (target users, target market, etc)
- Functional Requirements
- Non-functional requirements
- Defining the basic principles on how the app would get data and the APIs
- Defining the app architecture
- Deep diving in any of the feature
- Scalability

**Mindset that help me build an end to end system**: Thinking as if I am using the app and coming up with different scenarios and then discussing possible solution like

- What happens when the user goes on an airplane mode?
- What happens when the user removes the app from the background and then starts it again?
- What happens when the user uninstalls the app and re-installs it?
- What happens when a call or an alarm interrupts the app?

There is a lot that I could talk and I'd really be interested in taking a session if anybody is interested.

Hope this helps. Thank you!

Definitely Android Studio. Having working in Android since 7 years now I see Android Studio being used extensively to build Android apps. Although Android Studio is considered to be a heavy IDE the recent version HedgeDog is as smooth as it gets.

Take a book and whenever something annoys you write it down then brainstorm and see if you could do something about it through a mobile app. I'm sure you would find something meaningful to build. Although searching or asking for an idea to someone else would provide you a lot of options but I don't think these are the ideas that you are truly passionate about. So try to search for something that you are passionate about and want to solve the problem deep down. That's the way to succeed!

Having worked at Amazon, I can certainly answer your question.

For the first part - Android does possess a good future if you work in a company or an app that is mobile-first, like Instagram, Snapchat, TikTok, Uber, etc.

From my understanding, Amazon doesn't have a strong mobile engineering foundation for most of its apps. Having worked as an Android engineer at Amazon, I could sense a bias in career development compared to folks working in different domains. However, there is definitely a lot to learn if you end up working on one of their native, mobile-first Android apps like Amazon Audible, Prime Video, or IMDB.

I was lucky to work in Amazon Care (which no longer exists), where the app was built natively and with the most modern tech stack. I could tell that I received a strong foundation in Android engineering that catered to millions of people.

If you want to work in big tech company I'd recommend learning native mobile development. Nearly all major big tech companies build apps natively as they have the resources to manage the heavy cost that comes up with build natively. \
\
If you want to work at a startup or a mid-sized company or want to build something on your own where mobile is not the target device you should go with React Native.\
\
Also it's easy to switch from one technology to another as SWE skills are generally transferrable in most cases.

As a mobile engineer, I share a similar story to Alex's. I wanted to build something, and even today, Android boasts a superior ecosystem, making app publishing more affordable. I did spend a lot of time on learning unnecessary things, and if asked to start my software engineering (Android) career again, here is how I would approach it:

- Learn thoroughly about Object-Oriented Programming (OOP) in Java/Kotlin, along with basic data structures.
- Download Android Studio and understand the IDE, including its shortcuts (it will save you a lot of time).
- Try to pick the first step of your idea and learn while you build. Try to pull a string of your problem, solve it which eventually leads to several other strings. You keep solving them until you reach your goal of building a fully working Android app.
- Publish the app and add it to your profile.

That's the quickest way to learn Android engineering. Hope this helps!