How to Interview a Flutter Developer and What to Look For

Flutter candidates are in high demand across multiple industries and technologies today. Attracting and hiring the right developers is a tough task for even experienced teams. Our article on hiring Flutter developers has some initial tips and tricks on how to get started with finding the right candidates, but what about assessing applicants for Flutter development roles? What are the techniques and methods to highlight the best candidates and what are some Flutter developer interview questions to get started on the right track?

A platform first launched in 2018, Flutter is still a relatively new technology when it comes to application engineering. Compared to a platform such as Xamarin, developers haven’t yet had a chance to build up many years of experience and several dozen previous projects using the technology. Yet, in some scenarios, this can be a distinct advantage.

The Flutter platform provides opportunities to see how candidates learn new skills and techniques as much as they deploy existing ones to build solutions. As a result, Good Flutter developers tend to have a broader range of problem-solving skills and active participation in the development of the platform they use.

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Interviewing a Flutter Developer

In interviewing to hire a Flutter developer you’re seeking out a candidate with experience across multiple languages, diverging platforms, and most often native app development experience. Typically, this is a developer comfortable with diving deep into the workings of the framework to find and address solutions a little more outside the box than normal.

Our article on the best practices for Flutter development can be an invaluable guide to what a Flutter developer should and shouldn’t do in their role.

Essentially, you’re looking for a developer that can productively use rapidly evolving features as the framework changes and build robust applications that will last for years to come. Included here are the interview questions you can ask to help ensure that is the kind of engineer you find for your business.

Below are the questions to ask, the reasons to ask them, and the things to look out for to highlight the best quality Flutter application developers from the rest of the pack.

Soft Skill Questions for Flutter Developers

While technical questions and engineering ability get all the limelight in hiring a software developer, “soft skill” questions are at least as important to success. These questions tell you how well a candidate will fit in with the culture of a team and perform in an environment that may be unfamiliar and new.

Tell me about a situation where you had to do something entirely new. How did you handle it? What did you learn from the experience?

Diving into new technologies and learning new things is key to project success. In developing with a young, modern platform such as Flutter, these skill sets become even more critical still. Finding out how comfortable a candidate is working in an unfamiliar environment is a great way to gauge how successful new projects are likely to be.

Have you ever had to build an application within a difficult or unproductive working relationship? What was the core issue? How did you resolve it?

Effective teams are crucial to any development project. How well these teams come together can be directly measured in the quality and quantity of their product output. The ability to solve major problems is a major asset to bring on board.

How do you deal with conflict? What do you find effective when communicating something difficult?

Conflict resolution is imperative when dealing with complex tasks within teams. Ideally, your best candidate will have had experience navigating multiple types of team dynamics and is adept at interacting with various personalities. 
 

How do you manage your time?

Time management and honesty (with both self and others) about whether time targets are actually feasible are integral parts of building a trusting relationship between developers and employers. Can the candidate speak to a time when they had to reset a timeframe? How did they handle the communication of the time shift? What methods do they use to keep on track? As a developer answering this question, reflect on both successes and shortcomings to respond with what you have learned does and does not work. 
 

Think about a time when you faced a significant technical issue, but your manager was unavailable. How did you solve it then? How would you handle it today?

Finding out how far a candidate can progress independently, even against the odds, is a signal of how well they’re likely to progress without extensive micro-management. Finding out what they’ve learned from previous experiences can be a useful tool to see how they’re progressing through their careers.
 

Flutter Interview Questions - General Development

Until very recently, Flutter’s typical use case was rooted in cross-platform mobile app development. Having only been released in late 2018, the framework is likely to be a late addition to any mobile developer’s skill set. Senior developers will have experience creating apps using native tools or alternate frameworks in the past.

Asking questions about their general approach to mobile app development can give you a fuller sense of each candidate’s skills and qualities as a mobile application engineer. The questions below are intended to inform you of a candidate’s generalized skill set before focusing on Flutter interview questions.

Tell me about some of the mobile apps you have developed.

Asking a candidate to talk about their work highlights is the best insight you’ll get into how they can discuss technical topics. Choosing a topic they’d be expected to know very well and be passionate about too can set the right candidate up for success.

Here, a portfolio of previously published apps can help sell a candidate’s abilities better than anything else. Even if they’re not built using Flutter, they can tell you a great deal about a candidate’s abilities. You should have the opportunity to determine if their apps meet your expectations, whether they match the technical knowledge you’d expect, and whether you’d be happy with similar applications representing your organization in the marketplace.

Tell me about your greatest challenge as a mobile app developer and how you overcame it.

Since software development is, at heart, a profession based on the ability to solve problems—many of our questions focus on that aspect of the role. Asking about a developer’s most difficult professional challenges can tell you a lot about the depth of their experience.

Where do you see the future of Flutter development?

The answer to this question is investigated more fully in our article A Glimpse into The Future of Flutter Development.

Tell me about various technologies you’ve used to implement previous mobile apps.

Experienced app developers will have used technologies and frameworks outside of Flutter. Many will have used native application tools, cross-platform frameworks, or responsive web designs.

A great follow-up question should be to ask about the relative strengths and weaknesses of technologies they’ve used against each other and against other Flutter development tools. A complete answer to this follow-up should discuss implications on performance, user interface, and app functionality.
 

Flutter-Specific Interview Questions

You’re interviewing for a Flutter application developer, so it stands to reason you should ask questions on the platform itself. Asking the right questions beforehand should give you a firm idea of the kind of developer they are, how well they could fit into the organization, and the amount of experience they have under their belt.

These Flutter-specific interview questions should provide insights into how well they know the platform’s features and the Dart language too. Starting at the easier end of the scale and moving into more detailed topics, these questions will give you an insight into a candidate’s platform-specific experience.

What is a Widget in Flutter?

In Flutter, everything is a widget. From the app itself down through the code into UI components and views. Arranged in a tree structure, the UI of a Flutter app is constructed from nested widgets that define everything from layout to function and state.

Widgets have analogs in other frameworks too. In React, for example, similar structures are called components. A candidate may mention the similarity between the two. A senior developer may be expected to know that Flutter draws its own UI widgets while frameworks such as React Native render components into native code for the targeted platform.

What’s the difference between stateless and stateful widgets?

In Flutter, Widgets are split into two categories: stateless and stateful.

A stateless widget handles no data. They are created once and don’t store any values that may change over time. A stateful widget, in contrast, is dynamic in nature. Its values may update the UI and store values which influence the application in some way.

In the simplest possible terms: a user may manipulate a stateful widget such as an input field, text box, button, or slider.

Outline the lifecycle of a stateful Widget.

The full widget lifecycle, in order, should feature:

• createState()— A method called immediately on a stateful widget. The method should return a widget’s State object
• initiate()—The first method called after the widget is created
• didChangeDependencies()—Called the first time the widget is built and immediately after initState()
• build()—Called only once in a stateless Widget. In a stateful Widget, it’s called every time the UI needs to render the widget. The method should return a widget’s tree
• didUpdateWidget()—Called when there are changes to the parent widget changes the widget is forced to redraw its own UI
• deactivate()—Called when this object is removed from the tree
• dispose()—Deallocates memory for the widget and its state

What is a Scoped Model?

Scoped model is an architecture pattern that separates business logic from UI code. The advantages are the ease with which you can pass a data model from a parent Widget to its descendants.

What are some of the most impactful differences between Flutter and a Web application?

A good answer will focus primarily on the inefficiencies of a web application. Using various frameworks and tools can overcome some of the access limitations and drawbacks of a web application, but their inefficiencies and latency will always remain as a result of the various architecture layers required.

Flutter, in contrast, compiles Dart into native ARM code which will run more efficiently by design.

When might you use a Native app rather than a Flutter one?

This may feel a bit like a trick question when interviewing for a Flutter role, but knowing when to utilize a powerful tool and when not to is a crucial skill for developers.

When an app absolutely must be lightweight due to device restraints, legacy operating systems, or for instant apps, then a Native app—which is more lightweight by design—is often a more sensible approach.

How to Assess a Strong Flutter Developer

How a developer solves tough problems is every bit as important as the solution they come up with. Pay close attention to how they tackle practical exercises and the details they provide in response to solving technical challenges.

Code samples, written exercises, and a rich portfolio can go a long way to demonstrating the abilities of any candidate. If they’re provided for you to review, use them well. A glimpse at their coding style, commenting, and documentation can all be valuable insight.

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Intuition and Insight in Interviewing Flutter Developers

It’s not easy to find the ideal developer in any platform or language. The challenges of interviewing application developers are only made more difficult when discussing cutting-edge tools and technologies. The ideal developer interview should focus on highlighting not just technology-specific skills but creativity, soft skills, technical knowledge, and problem-solving ability too.

These questions, however, can’t determine all of that on their own. They’re merely an introduction to each of these qualities. They are an insight into how a candidate will respond to technical challenges and practical problems. They are an introduction to the specific problems and challenges within your firm that you’re asking them to solve.

Up next, check out what to do when you’ve assembled your remote Flutter team, The Do’s & Don’ts of Managing an Outsourced Flutter Development Team.
 

Flutter Interview FAQs:

Q1. Why should we hire a Flutter developer?

You should hire a Flutter developer if your company intends to develop apps for any of today’s leading platforms. Flutter is capable of delivering a unified application experience across separate devices and platforms with less time and effort in the development phases.

Key reasons organizations hire Flutter developers include:

• Excellent access to application plugins to leverage additional features
• Reduced development costs compared to native application development
• Rapid application development across multiple platforms with a single code base
• Reduced testing efforts with abundant tools and a unified code base to test
• Exceptional design credentials for applications across all platforms

A high-quality Flutter developer will design and develop apps for your firm, write clean and maintainable code to produce your applications, and identify new and emerging trends for your application to take. Despite being a relatively young technology, Flutter is enabling companies to do more with their development resources and target new ways of interacting with users.

Q2. How do I prepare for A Flutter interview?

Technical interviews are tough for both the interviewer and the candidate. You can prepare for a Flutter developer interview by brushing up on Flutter-specific technologies, general software developer problem-solving skills, and reviewing the technologies and tools you’ve worked with in the past for anecdotes and answers.

The first place to look when preparing for a Flutter interview is the platform’s own documentation and releases. Analyze what’s new in the platform, what’s changed in recent months, and what interests you about the technology that you think you could use in the future.

Next, take a look at the most popular and pressing questions that an interviewer is likely to ask. A simple Google search for ‘Flutter developer interview questions’ can bring up some of the most likely topics and help you to prepare answers that reflect your true skills and experience.

Finally, reviewing your own portfolio and CV can help you present yourself well and demonstrate the technologies and tools you’ve previously used.

Q3. What are keys in Flutter?

Flutter keys are parameters contained within the constructor of every widget. They allow developers to uniquely identify a widget within a collection or preserve state when replacing or shifting widgets throughout the widget tree.

In practical use, Flutter keys are used rarely, but they almost always prove to be exceptionally useful when they are needed. If, for example, your application has multiple widgets of the same type on the same level in the widget tree then updates may not happen as expected without having unique keys. You can explicitly set a key for each created widget to clarify which item in the tree needs to be updated as state changes happen.

One principal use of keys in a real-world application is to keep the scroll position of the user in a list of widgets and restore the view to that position when needed.