How to Interview a Mobile App Developer and What to Look For?

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Publish date:

October 20, 2021

Updated on:

March 7, 2024

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How to Interview a Mobile App Developer and What to Look For?


Hiring mobile application developers isn’t an easy task. The right decision can set you up for success, lead you to build outstanding applications, and create an environment built for success. But how do you know you’re making the right choices when it comes to hiring your next mobile application developer?

With just a couple of hours of conversation, coding, and crucial first impressions— the interview is critical to building your future teams. How you interview candidates for the role will define a lot about their success or failure within the firm.

Asking the right questions is the key first step in conducting a high-quality technical interview. Getting to know your future developers’ engineering credentials, design experience, and personality will help you find out if they’re a good fit for your organization and its existing culture.

Like any major technical project or management task, there are benefits to taking a careful, considered, and planned approach to the app developer technical interview. Starting with the basics, focusing on a candidate’s general coding ability and experience should provide a welcome introduction and allow applicants to lead with their best foot forward.

Later, moving on to more technical questions and practical exercises allows high-quality candidates to show off the depth of their experience and the coding style that makes them a highly valuable asset to bring into your firm.

Starting with questions to get to know your candidate and moving forward to the more technical and challenging parts of the role—our guide to interviewing mobile app developers is an ideal primer into how to interview technical staff to maximize success.

App Developer Interview Questions and Answers

Before even sitting down to interview your candidate, you should have a rough idea of what they’re capable of creating and the code they are able to write. While a thorough CV will give some insight into the technologies used, it’s a candidate’s portfolio that will help high-quality applicants shine and show off their technical skills.

The portfolio is the first and best chance at finding out what a candidate can create for you, and an opportunity to create some probing questions ranging from light and informal to the highly technical.

Looking at a candidate’s previous projects gives you a chance to ask about the technologies and choices made to get their applications to where they are today.

  • What drew you to work in this area of mobile app development? (Games, fitness, utilities, or entertainment for example)
  • Why choose the framework used to implement this project over other competing frameworks?
  • Are you familiar with the features, advantages, and drawbacks of alternate frameworks or native development for related projects?
  • Why were these architecture choices made over alternate options?

Having these questions to ask during a technical interview is a great way to get to the relevant topics of mobile app engineering and allow a candidate to demonstrate the work and experience they bring to the role. By asking about work they know well, you provide an opportunity for candidates to speak with authority and expertise on the subject and give them a chance to show their skills in the best possible light.

Mobile App Developer Basic Interview Questions

Before arriving at the technical points of mobile app development, it’s a good idea to start at the beginning and build from the basics.

For more senior positions this won’t be necessary, jumping right to discussing more recent projects will work just fine. Junior developers and fresh graduates, however, won’t have the same rich history of work to demonstrate and questions about the fundamentals of good engineering and application development will be the best possible indication of skills and abilities.

Describe the Most Difficult Project You Have Undertaken so Far. How Did You Tackle It?

A candidate’s answer to this question should demonstrate which areas of development a candidate enjoys the most and which areas they find most challenging. A good answer from an experienced candidate should relate to uniquely sticky problems that require creative thinking to deal with.

Finding out how a candidate deals with stressful tasks, their ability to solve challenging problems, and their areas of strength and weakness relative to the rest of the team is a highly valuable insight for a hiring manager.

How Is Developing for Mobile Different from Other Platforms? What Are Some Things Developers Have to Be Cautious of?

A successful mobile application developer should have an acute awareness of the challenges and limitations of the platform. It should be abundantly clear that even though the processing power of devices may be comparable to desktop machines, a solution designed for the desktop can’t always be plugged into a mobile app with success.

A good answer should consider some, or all, of a number of factors.

  • Limited network availability
  • Limited battery life
  • Finite amount of disk space available
  • Diverse array of devices available today
  • Limited amount of RAM in comparison to desktop

How Would You Choose a Framework to Develop a Mobile App?

Experienced mobile app developers often have experience building many applications over a handful of different frameworks or tools. Our list of the top mobile app frameworks available today highlights a few candidates that are likely to be considered and outlines some of the pros and cons of each.

A good answer should consider what is important to the application and take into account the specifics requirements and regulations of each platform.

  • Is it important that the apps look similar to each other on both Android and iOS? A framework such as React might be a good option if that is the case
  • Is it important that applications look native to the platform they are running on? iOS has some strict requirements about how its apps look and feel for users. Native development can guarantee an app’s look and feel but at a potential cost of doubling development efforts

Knowing how to effectively weigh one platform against another to asses the features that matter is a vital skill in mobile app development.

Get to Know a Candidate’s Coding Knowledge

One of the critical skills you need a candidate to have is knowledge of the languages you’re employing them to write. Some short, relatively simple questions to this effect will seem almost trivial to the right candidate. Yet, every hiring manager in the world has stories of candidates applying for positions without knowing the language specified. It pays to be safe rather than sorry.

A five-minute test, near the top of the interview, can save a great deal of time further down the road.

When it comes to testing candidates, there’s no substitute for simply looking at or creating code. Theoretical questions just don’t test the same skill-set. Code examples used later in the interview should be more complex than those used to test the basics.

If a candidate has a well-utilized Github repository, then lean on examples of work they’ve done in the past and ask questions about things they might change or do differently if they had more time. Otherwise, your own code can act as a good substitute test.

Removing comments and asking a candidate to describe its functionality is a great way to determine how much they know and what they can quickly pick up. The payoff is that a candidate who can show an understanding of production code at interview will have no problem settling into the team and getting up to speed.

Alternative options would be to implement a simple example program in the language specified. This can be a short question on pen and paper, to sort a simple list or complete a function specific to the firm’s area of interest. The goal of the exercise should be to demonstrate an understanding of the language, its features, and a candidate’s coding style rather than write picture-perfect code.

Ways to Test a Candidate’s Coding Skills

  • The best code examples come from your existing codebase as these are the problems the candidate is being hired to solve
  • A before and after snapshot of a bugfix within a method provides an excellent interview question with a ready-made answer with which to compare a candidate’s response
  • You may ask the candidate to talk through or document their solution to give you a deeper understanding of their professional communication skills

Practical Knowledge

A mobile app developer with some experience under their belt will bring a lot more value to the team than just coding know-how. Experience with various architectures, alternate ways to implement features, and different deployment methods are all invaluable when it comes to outlining the right strategy to move products forward.

It’s important to get an idea of each candidate’s experience in fields such as testing and continuous integration (CI). These are fundamental parts of professional app development that an experienced candidate should know.

Here you can build on work already done at an earlier round of questions. Asking a candidate to outline or write tests for code described earlier provides them with an opportunity to demonstrate a deeper understanding and gives you the chance to dig deeper too.

An Application Previously Published Occasionally Develops an ANR Error and Crashes, How Can This Be Solved?

A question that values practical experience and problem solving together, ANR is an issue that most developers will have seen, if not encountered themselves, at one point in time. ANR means application not responding, a dialogue box presented to the user if the system believes the app is frozen for more than 10 seconds.

The solution is to reduce the amount of work being performed on the UI thread by splitting out resource-draining tasks into threads of their own. Networking and database operations performed on a UI dependent thread are prime candidates in finding the causes of an ANR.

Given a Working App on a Developer’s Machine, What Steps Would Be Needed to Publish to Both Google Play and the Ios App Store?

Designed to demonstrate a candidate’s knowledge and experience working with mobile apps, the steps in both platforms are relatively straightforward though somewhat time-consuming.

Each of the two platforms will require image assets, written descriptions, and materials to support your app being displayed on the store. While many of these asset requirements will be similar, the precise list of what will be needed will vary slightly between both platforms.

iOS App Store

The first thing a publisher will need is an Apple developer account connected with the Developer program. Next, developers should create an app profile with iTunes connect.

The app is built to an IPA file which must be signed by Xcode using a distribution certificate and provisioning profile connected to the app ID.

Uniquely, Apple applications are reviewed before approval or rejection in the app store—a process that can take a few days to happen.

Google Play

Much like Apple, Google requires publishers to have a developer account to publish apps to their marketplace. With everything in place, the final app should be built to an APK, signed with a key that belongs to the publisher.

Once the signed files are sent to the store it may take a few hours for the app to appear on the store.

Big Picture Knowledge

More senior candidates should have an eye on both the day-to-day of application development and the broader picture of where work fits into a bigger scope. A developer who knows the entire process from design and architecture through to development, testing, deployment, and publishing is a highly valued candidate in mobile app development.

Our article on the pros and cons of mobile app development highlights the big picture knowledge necessary for developers to successfully navigate a project.

You should be able to ask a candidate to walk you through this process from beginning to end to get to know how they understand the development lifecycle. Compare each candidate’s answers to the company’s existing processes and assess how a candidate is likely to fit into them.

Is the candidate advocating for test-driven development, an agile approach, or something else entirely? It may be the case that the company can learn as much from the candidate as the candidate can learn from the company.

Candidates from smaller teams tend to skew towards shorter timescales with less room for slip. Candidates more accustomed to process and verification lean towards longer stages, increased time for testing and refinement, and more room for changes.

Ask for a Time Estimate for Each Stage of the Development Process

A time estimate is an easy way to gauge a candidate’s overall experience and practical knowledge in various areas of development. How do they break down the project? How many sprints do they dedicate to testing, deployment, and development?

How Can Features Be Added, Time to Market Be Reduced, or Additional Time Used to Best Improve the App?

Throwing in changes to the time available or features required can help demonstrate how a candidate responds under pressure and what they see as the most critical areas of the app. While these changes are fictional at interview, they are scenarios that occur often in real-world development and something developers regularly have to deal with.

Hiring a Mobile App Developer

To hire the right mobile developer with the limited time available, pay close attention to how candidates solve problems and, more importantly, how they communicate those solutions with the rest of the team. Communication is one of the best things you can test in an interview setting and should set you up for success with the right candidate going forward.

Follow the best practices to hiring and interviewing candidates and you can set off on the right foot towards landing the perfect team to build your future projects.

While no interview process will ever be 100% perfect, asking the right questions can provide the window you need to find the right candidate for the role. If you need help selecting the right company, tell us what you need. We can do the work for you and connect you with up to 5 companies within 72h that match your need-all for free.

How Do You Interview a Mobile App Developer?

Focus your efforts on an interview that allows a candidate to lead with their best foot forward. Ask about topics they’ve studied in the past, projects they’ve worked on in great detail, and technologies they’re comfortable with discussing at great length.

The technical interview should be a collaborative process rather than an adversarial one. Find out how well your candidate solves problems day-to-day, how effectively they can communicate solutions, and the things they value most highly in a technical project. Avoid trick questions and traps designed to catch candidates out.

You should approach the interview with the understanding that the candidate is interviewing your company as a valuable place to invest their time and skills as much as you are interviewing them to bring them on board. Good conversation, interesting topics, and an honest exchange goes a long way to creating a positive impression and creating the greatest insight for both parties.

What Skills Do Mobile Developers Need?

Mobile developers should be equipped with native development skills on both Android and iOS as well as some framework knowledge to implement cross-platform mobile applications. On Android, this means some Java or Kotlin knowledge in addition to experience of the Google Play ecosystem. On iOS, this means practical experience in Objective-C or Swift.

Knowledge of some of the most popular frameworks for mobile application development can also be a distinct advantage. React Native, Flutter, and Xamarin can each offer cross-platform solutions that can suit a wide range of mobile applications, for example. In short, the more practical skills and experience you can build in creating and publishing mobile apps for an audience, the better.

Practical experience creating applications for both platforms is the best education you can get when it comes to learning to build better mobile apps. Problem-solving skills, mobile-specific abilities, and practical tools all come from following best practices while working in the mobile domain.

What Experience Do You Need to Be a Mobile App Developer?

While some previous experience or formal education can be an advantage when it comes to being a mobile app developer, a personal portfolio of applications published to the app store speaks volumes about a developer’s knowledge and abilities. The best indicator of what a developer can produce is to look at the applications they’ve published in the past.

Whether these are games, utilities, or simply a demonstration of abilities—the best experience you can get towards being a mobile app developer is to create and publish mobile apps yourself. These will demonstrate your technical abilities, eye for design, a knack for detail, and ability to see a project through from planning to deployment. Simply developing mobile apps and marketing them to an audience is all you really need to be a mobile app developer.

Q1. How Much Does an App Developer Cost?

The average salary for mobile app developers worldwide today comes in at a little over $41,000. Regional differences, however, can skew this number in a big way. In the United States, for example, salary expectations are almost three times this amount. Where your teams are based and the technologies they rely on can play a significant role in costs.

The average mobile app typically takes between 16-20 weeks to design, build, and test ready for public release. While the costs for the tools and technologies necessary to deploy an app will add a little on top of this figure, developer costs are typically the most significant expense when it comes to mobile application development. Developers are, of course, the single biggest difference you can make when it comes to creating high-quality mobile applications that can truly reflect on your organization and teams.

Q2. How Do You Write a Job Description for an App Developer?

An app developer job description should be concise, specific to the industry and technologies used, and outline the expectations you have for the developer you intend to hire. A good job description should also detail the projects and assets that make your organization unique from the competition.

If your projects involve cutting-edge new technologies, different ways of thinking, or areas of interest that can make you stand out amongst the crowd, use them well. Your job description should advertise your organization as a place where app developers should want to invest their time, talent, and expertise for the duration of the project at least.

Be precise about the tools and technologies you’ve used in the past, and those you expect your next mobile app developer to come with. Be prepared, however, to take a flexible approach to developers shifting skill sets and changing tracks in development with a rich background of experience. Sometimes the best approaches come from different ways of thinking.

Q3. How Do I Find a Mobile App Developer?

Mobile app developers are in high demand today. Going through traditional routes such as marketplaces, LinkedIn, and business directories are still strong options that can connect you with teams. Posting the right job description to match your requirements, doing the research and due diligence ahead of time to find the right fit, and setting up an interview process to study the candidates can land you the mobile app developers you need to implement your next projects.

Of course, There’s no easier to find a mobile app development team than Pangea. With the due diligence, research, and vetting process done ahead of time—simply tell us what you need to be connected with vetted high-quality mobile app development firms selected specifically for you (for free!).


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Ian Deed

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Software developer, mobile application engineer, and writer helping companies to enhance their tech branding and improve the way they communicate with technical and non-technical audiences.

Leaning on years of experience and knowledge to understand technical communication that works from wordy jargon that doesn't.

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