You've just posted a job for a mobile app developer and your inbox is flooded with CVs from candidates claiming to be "React Native ninjas" and "Flutter wizards." Sounds great, right? Wrong. The harsh reality is that anyone can polish their CV and talk a good game during a phone call, but when it comes to actually building a quality mobile app, the wheat quickly separates from the chaff. I've seen too many businesses get burned by developers who looked perfect on paper but couldn't deliver when it mattered.
The challenge isn't just finding someone who can code—it's finding someone who can solve real problems, work under pressure, and create something users will actually want to use. Traditional interviews often miss the mark completely. You might spend an hour chatting about their experience with different frameworks, but walk away with no real understanding of whether they can actually build what you need.
The best developers aren't just good at writing code; they're good at solving problems that matter to real people.
That's where proper technical assessment comes in. This guide will walk you through proven methods for evaluating a developer's true abilities—from practical coding tests that mirror real-world challenges to spotting the red flags that could save you thousands in the long run. Because hiring the wrong developer isn't just expensive; it can set your entire project back by months.
Understanding What Technical Skills Matter for Mobile App Development
After years of hiring developers for mobile projects, I've learnt that not all technical skills are created equal. Some developers can write beautiful code but struggle with the basics of mobile performance—others know every framework under the sun but can't debug a simple crash. The trick is knowing which skills actually matter for your specific project.
The foundation starts with platform knowledge. iOS developers need Swift (or Objective-C for older projects) whilst Android developers should know Kotlin or Java. But here's what catches many people out: just knowing the language isn't enough. They need to understand platform-specific guidelines, memory management, and how apps behave differently on various devices.
Core Technical Areas to Assess
- Programming languages specific to your platform (Swift/Kotlin are the modern standards)
- API integration and handling network requests properly
- Database management and local storage solutions
- UI/UX implementation that follows platform conventions
- Performance optimisation and memory management
- Testing frameworks and debugging techniques
- Version control systems like Git
Don't get caught up in the latest trendy frameworks though. A developer who understands the fundamentals well can pick up new tools quickly. Focus on their problem-solving approach and how they handle real-world challenges like poor network connections or device limitations.
Planning Your Technical Assessment Strategy
Right, let's get straight to the point—you can't just wing it when testing developers for your mobile app project. I've seen too many businesses rush into technical assessments without a proper plan, only to end up with developers who can't deliver what they promised. The key is having a structured approach that actually tests what matters for your specific project.
Before you even think about writing test questions, you need to map out exactly what skills your mobile app will require. Are you building for iOS, Android, or both? Do you need someone who understands backend integration, or will they be working with existing APIs? These questions will shape your entire assessment strategy.
Building Your Assessment Framework
Your technical assessment should cover three main areas, and I recommend structuring it like this:
- Core programming skills relevant to mobile app development
- Problem-solving abilities using real-world scenarios
- Understanding of mobile-specific challenges like performance and user experience
Don't try to test everything at once. Focus on the top three skills that are most important for your project—this keeps the assessment manageable and more accurate.
Time and Format Considerations
Most developers can handle a 2-3 hour assessment without it feeling overwhelming. I'd suggest splitting this between a practical coding test and a discussion about their approach to mobile app challenges. Remember, you're not just testing their ability to write code—you're evaluating whether they can build something people will actually want to use.
Practical Coding Tests That Actually Work
After years of hiring developers at Glance, I've learnt that the best coding tests mirror real work situations. You don't need fancy platforms or complex algorithms—just problems that show how someone thinks and codes under normal conditions.
Start with a simple mobile app feature that takes 1-2 hours to complete. Ask candidates to build a basic login screen or a simple list view with data from an API. These tasks reveal so much more than asking someone to reverse a string or solve puzzles they'll never encounter in your actual project.
What Makes a Good Coding Test
The best tests focus on practical skills rather than theoretical knowledge. Give candidates the same tools they'd use on the job—let them Google things, use documentation, and work in their preferred environment. You want to see their normal workflow, not test their memory of syntax.
- Keep it under 2 hours maximum
- Allow internet access and documentation
- Focus on mobile-specific challenges like responsive design
- Include basic error handling scenarios
- Ask for clean, readable code rather than clever tricks
Review What Really Matters
When reviewing submissions, look at code structure, naming conventions, and how they handle edge cases. Can you understand their code without explanation? Do they write comments where needed? These details tell you far more about their day-to-day work quality than whether they completed every requirement perfectly.
Evaluating Problem-Solving Skills Through Real Scenarios
Testing a developer's problem-solving abilities isn't about throwing them a textbook question and watching them sweat. I've found that the best way to understand how someone thinks is by presenting them with actual problems they'd face when building your mobile app. Real scenarios reveal so much more than theoretical knowledge ever could.
Start with something concrete from your own app requirements. Maybe you need offline functionality when users lose internet connection, or perhaps you're dealing with slow loading times on older devices. Present these challenges and ask candidates to walk you through their approach. Don't just listen for the right answer—pay attention to how they break down the problem, what questions they ask, and whether they consider user experience alongside technical solutions.
Creating Realistic Test Scenarios
The scenarios you choose should reflect actual development challenges. Battery drain issues, memory management problems, or API integration failures are all excellent starting points. Give candidates time to think through their response rather than expecting instant solutions.
A developer who asks clarifying questions about user behaviour and device constraints before suggesting solutions shows they understand mobile app development goes beyond just writing code
Watch how they handle uncertainty too. Mobile development is full of unknowns, and the best developers admit when they don't know something whilst explaining how they'd research solutions. This skill verification approach gives you genuine insight into their technical assessment capabilities and problem-solving mindset.
Assessing Communication and Collaboration Abilities
I've worked with brilliant developers who could code circles around anyone but couldn't explain their work to save their lives. And let me tell you, that's a recipe for disaster! Your developer needs to communicate clearly with you, your team, and potentially your clients. They don't need to be a natural presenter—most developers aren't—but they should be able to explain technical concepts in simple terms.
During your interview, pay attention to how they describe their previous projects. Can they break down complex problems into bite-sized explanations? Do they ask clarifying questions when something isn't clear? These are good signs. Watch out for developers who get frustrated when you don't understand something immediately or who use technical jargon without explaining what it means.
Key Areas to Test
- Ask them to explain a complex technical decision from their portfolio
- Present a hypothetical client request and see how they respond
- Test their ability to give realistic timelines and explain potential roadblocks
- See how they handle feedback or criticism of their work
- Check if they can admit when they don't know something
Remote work has made communication skills even more important. Your developer needs to update you on progress, flag issues early, and work well with your existing team. A developer who communicates poorly will cost you time, money, and quite possibly your sanity!
Checking Previous Work and Portfolio Quality
A developer's portfolio tells you everything you need to know about their abilities—well, almost everything. I've reviewed hundreds of portfolios over the years and there's a clear difference between someone who knows what they're doing and someone who's just getting started. The key is knowing what to look for.
Start by examining the apps they've actually built and released. Are they still available in the app stores? Do they work properly when you download them? I always test a few of the apps myself; it's amazing how many developers showcase apps that crash on launch or haven't been updated in years.
Quality Over Quantity
Don't be impressed by a portfolio with 50 apps if they're all basic calculator clones. Look for variety in complexity and functionality. A good developer will show you apps with different features—maybe one with complex animations, another with payment integration, and perhaps one that uses device sensors.
Pay attention to the user interface design quality too. Even if they're not designers, experienced developers understand good UX principles and can spot when something doesn't feel right.
Ask developers to walk you through their code architecture for one of their portfolio apps. This reveals whether they actually built it themselves and understand the technical decisions behind it.
The Devil's in the Details
Check if their apps have good ratings and recent reviews. Look at the app store descriptions—are they professional and well-written? These details show you're dealing with someone who takes their work seriously and understands the full mobile app development process.
Red Flags to Watch Out For During Technical Interviews
After years of interviewing developers—and making more than a few hiring mistakes along the way—I've learned to spot the warning signs that suggest a candidate might not be the right fit. These red flags can save you from costly hiring decisions and project delays.
Communication Warning Signs
Watch out for candidates who can't explain their code in simple terms. If they ramble with technical jargon when you ask basic questions, they'll struggle to work with your team. I've seen brilliant coders who couldn't communicate their ideas, and it always caused problems later.
Pay attention to how they handle questions they don't know. Good developers will say "I don't know, but here's how I'd find out" rather than trying to bluff their way through.
Technical Red Flags
Here are the main technical warning signs to watch for:
- Can't explain basic concepts in their claimed area of expertise
- Copies code directly without understanding what it does
- Shows no interest in testing or code quality
- Dismisses security concerns as "not my problem"
- Claims expertise in every technology but can't demonstrate depth in any
- Gets defensive when you question their approach
Trust your instincts. If something feels off during the interview, it probably is. A good developer should make you feel confident about their abilities, not confused or concerned.
Conclusion
Testing a developer's technical abilities before hiring doesn't have to be a nightmare—though I'll admit, I've seen some companies make it far more complicated than it needs to be! The key is finding that sweet spot between being thorough and being practical. You want to learn enough about their skills to make a smart decision, but you don't want to put them through weeks of assessments.
What I've learned from working with hundreds of developers over the years is that the best technical assessment combines multiple approaches. A quick coding test gives you a snapshot of their abilities; a portfolio review shows you what they can actually build; and a good conversation reveals how they think through problems. None of these methods work perfectly on their own, but together they paint a pretty clear picture.
The mobile app development world moves fast, and technical skills are just one piece of the puzzle. Someone might write beautiful code but struggle to explain their decisions to your team. Another developer might have a few gaps in their knowledge but learn quickly and communicate brilliantly. That's why assessing communication and collaboration abilities matters just as much as checking if they can build a working app.
Trust your instincts during the process—if something feels off, it probably is. Good developers are out there, and with the right approach to skill verification, you'll find them.
