Complete hiring guide for Xamarin developers

There are many aspects and benefits to working with Xamarin, and its usage and popularity seem to be more in demand and increasing. Let’s find out how this works, the need of Xamarin developers, how to find and interview them, and what working with Xamarin encompasses.

Cross-platform app development seems to be on the rise compared to native app development. Specifically, in this case, this is due to the reduced costs, in the long run, the code sharing and reusing, as well as overall functionality. Xamarin developers are in more considerable demand than before due to this.

In our complete hiring guide, you’ll learn more about this platform’s popularity and usage, the developer’s job position and obligations, tasks, challenges, stats, and more.

About Xamarin

Xamarin is an open-source tool platform released in 2011. It is used to create and build performant applications for iOS, Windows, and Android, all through the programming language C#.

It is an abstraction layer that manages shared code communication with platform code, and it runs in a controlled environment with memory allocation and garbage collection features.

With Xamarin, the developers can manage and communicate shared code within an existing platform code. To sum it up, it means all developers can share more or less 90% of their applications to several platforms.

Xamarin is natively compiled, and developers almost always prefer it to build apps of high performance that feel and look native.

With Xamarin, you can build native apps for iOS and Android and native apps for Mac and Windows. However, this said, a developer cannot use Xamarin for web-based deployment.

Stats about Xamarin

The stats about Xamarin provide good feedback in general.

The salaries of Xamarin developers differ slightly from one position to another. A senior software engineer has an annual salary of $120.885, whereas a software engineer has $126.942 annually.

Furthermore, a fullstack developer has a $101,929 annual salary on average, and we see a more significant spike in the mobile developer position, with $123,831 annually.

In a survey from Stack Overflow 2021, Xamarin’s popularity as a tool had a percentage of 4.17%, and 43.32% prefer working with it, whereas 56.68% mostly avoid working with it. But in recent times, Stack Overflow 2022 shows a slight increase in Xamarin’s popularity – 5.54% like to work with it, and this is out of total 41.060 respondents.

We see that the percentages differ, but not way too majorly.

Popular brand names that rely on Xamarin usage

Here are some brand names that use Xamarin, out of many:

1. Storyo Video Story Creator
2. Captio: Travel and expense management
3. Pinterest: Virtual discovery engine corkboard
4. Fox Sports
5. Siemens
6. The World Bank: Survey Conducting App
7. Just Giving: Online Fundraising Platform
8. Insightly: CRM and Project Management
9. Olo: Online Food Ordering Platform
10. Skulls of the Shogun: Gaming App
11. FreshDirect: Online Food Grocer
12. APX: Environmental Asset Tracker
13. SuperGiant Games: Console Game for Mobile
14. Thermo Fisher Scientific: Research and Development

Interviewing a Xamarin developer

Helpful tips for a pre-screening interview

A talent acquisition specialist focuses on several key factors and crucial things during the interview with a Xamarin developer. They ask specific questions to assess the developer’s experience and expertise through a few things.

Apart from asking about the years of experience and daily work done with Xamarin, they also focus on English proficiency and soft skills throughout the interview process. This guarantees the cooperativeness and responsiveness of the developer and confirms they would have an unobstructed relationship with the clients.

Technical skills of a Xamarin developer

An experienced Xamarin developer has to have experience with:

• Working with C# Xamarin for iOS and Android apps
• Having experience with .NET and XAML
• Knowing Object-Oriented Programming
• Building apps from scratch and maintaining them
• Resolving app bugs
• Understanding MVC and MVVM design patterns
• Having experience with SQL, Notifications, Ads, Firebase
• Having experience with Microsoft Visual Studio and Xamarin Studio

Non-technical skills of a Xamarin developer

Recruiters and talent acquisition specialists overlap in their answers when asked about the non-technical skills of a Xamarin developer.

An accepted norm is for the developer to exhibit substantial and above average English language proficiency because this is crucial for client-developer communication without obstacles. Visible communicativeness and openness to discuss the job position and the portfolio are greatly useful for the overall interview call.

Xamarin interview questions and answers

The following questions are just some of the numerous ones good to consider for assessment of the skills and expertise of a Xamarin developer during the interviewing. Enquire about:

1. Which programming languages are supported by Xamarin?

Expected answer: With Xamarin, when we build mobile apps, we can choose C#, but also Visual Basic.NET, and F# too.

2. Define Xamarin Profiler.

Expected answer: Xamarin Profiler represents a practical tool for analysis of the app and its behavior. This tool was created and released by Microsoft. This tool doesn’t just analyze the overall performative behavior of the app but also analyzes allocations of memory of the app. Xamarin Profiler does all of the above-mentioned through Visual Studio, representing a neat and practical interface for graphics handling and building apps. We have to be inside Visual Studio to do this.

When we use Profiler, we get many benefits, like where we should dispose of unneeded memory leaks within particular objects.

3. What can you say about Xamarin Insights?

Expected answer: With the help of the tool Xamarin Insights, we can closely monitor and pinpoint/identify any events, stats, faulty patterns, and problems in an app. Some of the things we observe in this case would be page views, operations’ length, as well as button touch issues. All of this is done in real-time, and we get access to both past and present sessions. Additionally, we get an in-depth insight into all those features in the app that are used and those that are not.

4. Can you define ‘data binding’ in Xamarin?

Expected answer: As a crucial part of the MVVM (ModelView-ViewModel) app architecture, with the process of ‘data binding’, we are connecting or linking the properties of two separate objects, and at the end of this process, we notice how one property is reflecting the changes in the other property.

In other words, we connect the UI of the app with its displayed app data. The connection is between a source and a target. We can find out which properties precisely we can bind (which ones are bindable) through the usage of Xamarin.Forms.

5. Can you differentiate between Xamarin and Xamarin.Forms?

Expected answer: Xamarin represents a platform, i.e., a tool for developing apps that are open-source too. With Xamarin, we can create apps for Android, iOS, and Windows using .NET (an open-source platform for app building). Through Xamarin, devs can easily share almost all of their app content on more platforms and even use just one language to write the business logic. We can write the apps on Mac or PC, and the following step is compiling them in native-app packages (these are .ipa for iOS and .apk for Android).

Xamarin.Forms is a UI framework that’s open-source, cross-platform, and used for developing apps from just one codebase that’s shared. When we devs use Xamarin.Forms, we place the code just behind C#, and we use XAML (Extensible Application Markup Language) for the user interfaces. It is excellent for testing and sharing code, as well as sharing business logic on more platforms. Also, it’s good for designing on platforms and sharing the layout of the UI.

6. What is XAML?

Expected answer: XAML (Extensible Application Markup Language) represents a markup language that’s declarative, incredibly useful for GUI (Graphical User Interface) description, and it immediately shows us the instantiation, as well as execution of an object. Also, XAML is widely used for creating UIs of apps.

With XAML, we can make visuals in the UI components, and it’s not too similar to other languages for markup use. Several parties can work with different tools simultaneously in the UI and the app logic. XAML allows UI defining during the development of Xamarin apps, and it is not obligatory to use with Xamarin.Forms, for example.

XAML works with the app architecture MVVM (ModelView-ViewModel).

7. Elaborate on Xamarin Live Player.

Expected answer: If we want to make live changes in the app that do not require deployment cable or emulator, and to have those changes be seen live, we use a tool named Xamarin Live Player. With it, debugging and testing get more practical and simplified too, and the great thing is that we don’t need to work with a physical device for this whole process.

Upon installing a small size app to the device, a communication is established between the development machine and its Visual Studio IDE (Integrated Development Environment) contained within that machine for development.

In summary, we devs can quickly deploy apps to Android and iOS devices when we use Xamarin Live Player.

8. Describe the ListView and TableView.

Expected answer: The list view and Table view are controls in Xamarin.Forms.

ListView is used in numerous ways only if we have lists of data that are scrollable, and this class offers support for data binding, as well as context actions. On the other hand, with ListView, there is no support for XAML items defining. It’s best when we use ListView for any collections that are just a single type of data. ListView presents the data vertically stacked.

TableView is used for viewing the lists of data that are scrollable horizontally, and this is applicable for those sections of rows that have different templates and not a shared template. Compared with ListView, we conclude that TableView requires manual addition of items, and ListView does not require this due to the ItemSource concept.

9. Can you explain more about the command ‘i’ in Xamarin?

Expected answer: If we want to share the ViewModels successfully between Xamarin.Forms apps, and the Window apps, we use the iCommand that’s implemented through a Window class.

The iCommand interface is the link between BusinessLogic layer and Presentation. Let’s try to explain through a process example.

If we don’t use an MVVM during app writing, we need an event handler subscribing, and we need to thus easier manage the UI with the user's interaction (even something as simple as a click by the user). This makes a newly create method (in C#), and once we raise the event, the code within the created method will execute successfully. With this, we strengthen the regulation and View correlation. The overall approach uses unique objects (commands) which apply the interface iCommand.

10. What does ‘outofmemoryexception’ mean? How would you handle this?

Expected answer: The ‘outofmemoryexception’ represents a bug we might notice in the development process. This bug lets us know there is not enough contiguous memory for all those allocations that C# requires and also that there is insufficient memory in general.

The optimal solution is heap size increasing, i.e., increasing the objects’ memory being used.

Some steps you can try out to resolve this is first to go to Visual Studio and open it. Then find the Android Project and right-click on it. After that, you’ll see and choose Properties, and finally, there you can choose to enlarge the heap size, for example, 1G heap increase.

Essentials and assessment of a Xamarin developer

When you start looking for the best Xamarin developer, there are some essential things to look for:

• Confirmed knowledge of cross-platform development
• Expertise in Visual Studio and C#
• A good understanding of MVVM (Model-View-View-Model)
• Code reusability expertise
• Knowledge about Android architecture
• IoC concepts expertise
• Dependency Injection knowledge

We asked Koray Biçer, a senior software developer, about the essentials that a Xamarin developer has to have and how they assess them:

“It is important to ask the potential candidate about MVVM, XAML, Views, Page Layouts, Master-Detail Page, and REST Services data retrieving. Another way to assess the expertise is to ask the developer to write a small sample application that would fetch information from a remote API and display it”.

Koray Biçer

Also, Kerem Özcan, a mobile application developer, said:

“The developer needs to have good expertise in OOP, .NET, C# of course, UX, and application life cycle. Plus, we would need to ask about experience with Azure, UI testing, and App Center to assess the skills. But, in the end, I also want to look at the GitHub account of the candidate to find out more about the past experiences and projects.”

Kerem Özcan

What distinguishes a great Xamarin developer from a good one?

A great Xamarin developer stands out from a good or average one through knowledge and development on Xamarin Forms and Xamarin Native. Of course, it is an additional bonus point to work with Java, Kotlin, Swift, and C#.

Other significant assets of an excellent Xamarin developer are the experience with GRAPHQL and REST, APIs, lambda expressions, LINQ, and asynchronous and reactive programming.

Possible challenges during the hiring of a Xamarin developer

Usually, a developer needs to have substantial experience to work with Xamarin, despite the simplicity factors of this platform.

Xamarin does not use the JavaScript directly and uses C# for the same JavaScript segments otherwise. This is not a major challenge, but the developer would need good expertise and avoid any complications of the whole repository later on due to this.

The possible challenge is that a developer could lack some files and information for the Xamarin implementation process. This platform is not old, but because it is released in 2011, it is somewhat new. Due to this, if the developer needs some quick solutions to issues, they would need to enter a large community to consult other experts.

As seen in the sections above, Xamarin has popularity with a limited number of developers, making its demand more valuable.

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

You need to hire a Xamarin developer if you are ready to take your project to another level. Namely, the usage of Xamarin is for those that need to share code and test across platforms. Not only that but also writing applications of cross-platform type with Visual Studio and C#.

If you want more than one app developed, you will need to hire one developer for each team that handles the operating systems. Or another option is to hire a few developers specializing in app building for more operating systems at once.

In summary, you need to use Xamarin for your project, or hire a Xamarin developer, if you need building of mobile apps in a simple, efficient way, with shared codebases. With it, you will get an excellent result of UI elements that are platform-specific.

Benefits of Xamarin

Xamarin is as unique as it is in demand, making all factors related to it all the more captivating. This is mainly because Xamarin allows fast and efficient single language use (C#) for coding an app.

Another significant advantage of it is that it offers a rich library. Add an excellent runtime environment, and Xamarin appears to be even more attractive for developers’ work.

When developers start using Xamarin, they need just one machine to cover all environments used.

Regarding saving on resources and finances, Xamarin works toward this through easy maintenance and code sharing. For example, cross-platform native usage uses up less memory, less CPU time, runs faster, and loads more giant data sets than Hybrid HTML.

Further, another perk of Xamarin is the smooth Azure Cloud integration. This provides a stable and incredibly secure mobile backend cloud—a few simple code lines and that’s it.

Using this platform allows for the following:

• Writing of the apps in C#
• Building of native UIs
• Utilizing MVVM design patterns
• Good API integration
• Shared codebase
• Fast development
• No issues with hardware compatibility
• Functioning well on wearable tech, too, not just some smart devices
• Cross-platform app development
• Low maintenance costs
• A community of users that increases over time

Developers that like working with Xamarin like it for several reasons. One obvious reason is the C# usage that makes the process fast and easy. So instead of relying on Objective-C, Swift, or Java without any leeway, everything can be completed with C#. Biçer further said:

“I like that I can develop all the code with a single language like C#. I can also develop the UI just one single time and run it on all platforms. The code-sharing is very easy between platforms, and I need less time for app maintenance”.

Besides, when the developer uses Xamarin.Forms they save time by app releasing in different stores at the same time.

Another big reason for preferring Xamarin by developers is that the final UI turns out exactly as expected—realistic, smooth, and satisfying to use.