Complete hiring guide for Flutter developers

About Flutter

To create visually appealing, multi-platform, and natively compiled applications with the use of one codebase, Flutter is the best option as an open-source framework. It provides a productive workflow, flexible and fast, and enables complete control over every pixel for a gorgeous outcome of adaptive and customizable designs.

Flutter enables simple and easy deployment to all embedded devices, not just mobile, desktop, and web. Also, the workflow is simplified and more efficient through total control of the codebase through tooling for developers, automated testing, and all features and perks that lead to top-quality applications created.

Google also uses and supports Flutter, making this framework a favorable one globally and supported by a large community of brands and developers.

Demand for Flutter developers and stats

Since Flutter as a framework is relatively new, the demand for Flutter developers is steady or rising to keep up with the novelties and benefits in the tech world whenever introduced.

Because Flutter is a functional, reliable, and efficient framework, its demand rises constantly. Finding a suitable fit is also getting more manageable and time-saving because the community of Flutter experts is continuously enlarging, saving everybody some time—from employers to developers seeking a job.

A survey from Statista has shown that between 2019 and 2021, Flutter was the most popularly used for cross-platform development, with a substantial percentage of 42%, and the rise continues at a steady pace.

What exactly does a Flutter developer do?

A Flutter developer works on cross-platform mobile applications development, creating both Android and iOS applications with no need of code writing separately for the two and simply relying on the one, single codebase. Ideally, a Flutter developer must obtain and use good knowledge of the Dart language and JavaScript, CSS, HTML, and even the IDE Android Studio.

Why and when do you need to hire a Flutter developer?

Hiring one or more Flutter developers is your go-to option when something needs completion quickly. When the developer finishes the work, the launch of a finished product goes speedily and almost immediately. Whether you choose a single hire or a team, Flutter developers can finalize something with excellent results within a quick timeframe.

Interviewing a Flutter developer

Helpful tips for a pre-screening interview

The first and crucial step in hiring a Flutter developer is made by recruiters and experts who organize and do the interview, but this process needs meticulous planning beforehand. Like any other hiring process, in this case, the Flutter developer has to meet all criteria for the company.

The process is familiar to everyone—it starts with essential getting to know each other through questions specific to the job position. After this, the following steps are more specific questions, or in most cases, tasks and practical tests of the skills.

Almost all hiring specialists are on the same page when it comes to hiring developers, or more precisely, in this case, Flutter developers.

The ideal candidate will have good experience and soft skills; the more, the better. Any developer that would enter a new workplace and team has to communicate well with the other team members because miscommunications could be an obstacle to the workflow. Also, the candidate has to be polite, respectful, and have a good knowledge of the English language.

Top technical skills to look for in a Flutter developer

An excellent Flutter developer has to attain various technical skills for practicality and functionality. Hiring, in this case, becomes even more intriguing because Flutter is a new framework to some extent, and perhaps a handful of developers would be the best match out of numerous applicants.

A great Flutter developer will primarily know how to:

• Fix bugs efficiently
• Write a clean code
• Investigate technologies for fast development
• Take part in life-cycle development
• Be up to date with the latest development trends
• Develop and design apps

However, as we delve deeper into the technical skills of a Flutter developer, without exception, there needs also to be:

• Knowledge and experience with the Flutter framework
• In-depth expertise and knowledge of Git
• Understanding of software development life-cycle
• Dart programming language experience
• Expertise in iOS or Android mobile development services
• Quality knowledge of Computer Science
• GoF patterns experience
• Architecture approaches experience
• SQL expertise
• Knowledge of Swift and Kotlin

We asked Zoran Conevski, a full stack developer, to share some of the expert technical skills a Flutter developer should have. He says:

“Good knowledge in software architecture is crucial and knowledge in Dart and system design. Hand in hand with this, it is a must-have for a Flutter developer to know how to set up the suitable and proper app architecture, which makes the project maintainable and easy for usage and control in the long run. Additionally, Dart and Flutter's best practices are desirable, especially regarding optimization and performance”

Zoran Conevski

What sets apart a great Flutter developer from a good one?

A great Flutter developer differentiates from a good one, adds Conevski, primarily by the way they use and implement the app architecture, all state management solutions, and of course, the testing itself.

“A great Flutter developer will create and write all the tests for the Flutter apps. Most of the time, a great Flutter developer has tried several different architecture approaches, and they also express their opinion freely about how they would do things. They should also be able to explain why they would do something different and back it up with valid reasons.”

How Proxify helps you find the best Flutter talent

Finding a great developer is not the most uncomplicated challenge in the career world, especially when you ask for no help and do the process alone.

It can be time-consuming and tiring because usually there are many applicants, and most of them will probably be a good fit—but the most significant challenge would be to make a selection that leads to a perfect outcome. Interviews take time to complete, and it is not all just receiving applications and preliminary discussions with the applicants.

The first crucial thing is dedicating a reasonable amount of time to complete the whole process. Also, planning and setting aside needed resources and appointing specific recruiters and talent acquisition specialists is another crucial component.

Additionally, experts will prepare things and take care of onboarding and, if required, training. This process will introduce the candidate to the company and the job obligations.

But imagine how tiring the process would look without help and if it was a one-person task. Quickly selection without much thought will cost significant resources down the road, not to mention repeating the whole interview and hiring process from scratch and losing precious time.

At Proxify, we have excellent talent acquisition specialists and recruiters who pay close attention to every applicant by carefully yet time-efficiently selecting candidates that would continue in the following phases, thus being aware of time limitations. Every single selection process is successful with highlighting the candidates that stand out first thing when the interviewing starts to take place and:

1. Preliminary tasks for self-assessment to shortlisted developers
2. Scheduled call with the recruiters as a pre-screening phase (to those that submitted a successfully resolved assignment as a first and previous step).
3. We focus on technical and non-technical skills, proficiency in the English language, and substantial, good quality expertise and experience of the candidate in the past.
4. Assigning a practical task or test that confirms the core skills needed for the job position
5. Finalizing with a technical interview led by a Flutter developer

We pay great attention to every candidate's skills and expertise so that a great Flutter developer does not ‘slip through elsewhere’ as a potential new hire. Paying attention to timeframes and carefully checking all submitted tasks and tests guarantee that the best Flutter developer is selected every single time.

In a fast-moving and ambitious career world where agencies take the interview process lightly or irresponsibly toward the company and applicants, we at Proxify make an excellent candidate selection without losing track of time and always welcome the utmost best applicants.

Essentials and assessment of a Flutter developer

The right person to answer questions about Flutter developers is primarily Flutter developers. We asked about personal opinions regarding good assets and skills in a developer that would join a team and the focus during the assessment process, what is good to have regarding technical expertise, and similar.

As in the sections above, in this exact context, Zoran listed the following check-points for discussion and assessing the Flutter developer better:

• Hands-on experience with building Flutter apps
• Naming the most complex thing implemented through Flutter and how the developer implemented it.
• Questions about an app architecture
• State-management solution
• Testing of Flutter apps

He also added:

“To assess a Flutter developer, I would ask most about architecture, Dart programming language, and state management. I clearly understand the skills, mostly with these checkpoints and questions, especially if that developer had experience with larger projects. When discussing such points, I know that developers also have good knowledge for approaches and best practices”.

Benefits of Flutter

Many benefits are associated with Flutter, but it is good to work with it due to the shortened time for writing code and broadening its community of users.

Plus, there is the individual rendering engine with custom widgets for iOS and Android; the platform is also simple to understand and implement. Additionally, you can run Flutter apps in browsers without changing the written code. If there’s a need to create and develop new features, you will reduce the development time from one or a few months to just less than a month.

The UI looks visually gorgeous with widgets that contribute to what you see on the screen. Also, costs are reduced with Flutter because one single team can make the native apps development instead of separate ones for iOS and Android.

For developers, a great benefit is that they can easily handle the Dart language needed for Flutter if they know languages like C or JavaScript, which is the case most often.

What benefits did Flutter developers mention?

The benefits of working with Flutter are numerous, but those that stand out significantly are:

• Quick MVP/prototyping,
• The time for development and how fast this process goes,
• A lot of packages included,
• An open and friendly community of experts

Regarding practical usage, Zoran added,

“We use Flutter for cross-platform mobile app development for iOS and Android. With the recent upgrading in the years, it can now support platforms like Web, Desktop (Mac, Linux, Windows), and such embedded devices. Amazingly, you need just one code base for software building that successfully runs on mobile, desktop, and web”.

Flutter interview questions and answers

1. Briefly describe and define Flutter.

Expected answer: Flutter represents an open-source framework used for building, testing, and deployment of web, desktop, and mobile apps, as well as embedded apps. It uses just one codebase and also makes use of the programming language Dart for the app creation and simplifying of the development process.

2. What are the most essential features of Flutter?

Expected answer: Flutter reduces the time needed for code development with its ‘hot reload’ feature, where the dev can see all changes quickly. Another perk of Flutter is the usage of the same business logic and UI for all platforms—it enables sharing UI and the UI code, while other frameworks don’t allow this. Then, the time-to-market speed is also increased with Flutter. Additionally, the performance is similar-to-native and makes the UX outstanding. And lastly, the UI can be customized and animated too.

3. What are the evident Flutter ‘flaws’ or limitations?

Expected answer: If you want to create some Unity integrating, or 3D model creation of something, or even include game engines within, it can be pretty complex to do so with Flutter. Another flaw to mention is that if you need support, there is only the community to consult on this. Still, it doesn’t get broader or massive support other than the internal community. Also, Flutter has somewhat limited libraries and sets of tools overall. Another to mention is the not-so-ideal support for iOS features.

4. What are Flutter build modes?

Expected answer: When you are in a specific development phase, your code is compiled in various modes, and the framework does this itself. These multiple modes are called build modes. Flutter has special tools that compile your app in three modes—Debug, Profile, and Release.

5. Explain the three modes of Flutter and their roles

Expected answer: Flutter’s modes are Debug, Profile, and Release.

Debug mode simplifies debugging of an app that is found on a simulator or physical device. Here you also use service extensions, and quick deployment runs smoothly too.

The Profile mode still has some debug features that do the trick well enough during the testing phase. You can compile Profile mode with the command: flutter run --profile

The third mode, Release, is used in the app deployment, and it’s great for better optimizing and reducing the footprint. On the other hand, in this mode, there are no service extensions or debugging available. To use this mode, type the command: flutter run --release

6. How important is Dart in the context of Flutter? Or, what is the correlation between Dart and Flutter?

Expected answer: Dart is a programming language. In the context of Flutter, Dart is used for coding of apps and coding of a server too. The main benefit of using Dart with Flutter is that there’s no need for using separate layout languages like XML or JSX. Dart’s layout is programmable and declarative, easy for visualizing and reading. Another reason that makes this tandem powerful is the just-in-time usage by Dart, so the responsiveness and development time are shortened.

7. Define and elaborate on the Flutter Widgets.

Expected answer: When the dev starts working or coding in Flutter, the process will be seen in the widgets. Flutter widgets describe or showcase the perfect look of the app as it is in the present or with the current state look and configuration. If the dev makes a certain code change, the widget itself will change and reconstruct itself accordingly. This widget reconstructing is done when the widget calculates the difference between the previous and current widget, so the result is the number of minimum changes (in quantity) that are needed for rendering the app UI.

8. What is the Flutter widget ‘Container’?

Expected answer: The Container in Flutter is a widget used for composing the ‘child widget’ in Flutter, personalizing it, adjusting its position, and decorating it too.

9. What is the BuildContext of Flutter?

Expected answer: When you need to track all the widgets within the tree and find their location and tree position, you use the BuildContext locator. As its name says, BuildContext is a locator for the tree widgets and their positonings.

10. Explain what a Tween Animation in Flutter.

Expected answer: The Tween Animation is also known as Tweening, and this is short for ‘inbetweening’. The process of tweening means image generating that occurs between keyframes or images. These keyframes are images that mark the start and end of a certain transition. A straightforward example of a keyframe is when an animated object moves from point A to point B, or an animated character jumps from one spot, and lands on another.