Hire iOS Developer Freelancer: Things to Consider, Mobile Trends, and Interview Questions

Things to consider when looking for an iOS app engineer for your company. Mobile trends and hard interview questions many candidates will struggle with. Swift, Google Flutter, and React Native – which technology to choose for mobile app development.

Tom Potanski

Last updated on July 12, 2020 | 17 min read | Language:

• English
  • German
  • Swedish

BusinessGuideMobileOutsourcingSoftware development

The importance of mobile development for businesses

Small businesses (SMB) are no exception to this trend. A few years back, most of the mobile applications on the market were created by huge corporations. However, thanks to the increase of mobile application usage, small businesses are now driven to mobile app development to stay competitive.
According to recent statistics, mobile apps are projected to generate 188.9 billion US dollars in revenues in the year 2020. That revenue is just from app stores and in-app advertising alone. Not every SMB will be able to afford the costs of developing an app. There is the option to create a mobile responsive website as a response to the mobile demand.
However, it is noteworthy that SMB’s who can afford to develop both often come out on the top.
It is not simply the pressure from mobile users that pushes mobile application development. They often use these applications to increase sales by improving their brand image. One of the ways to improve the brand image is through the use of mobile applications. By improving client service, client loyalty is improved.
Another use of these apps is to simplify or improve certain business processes. Users can book appointments, order products, get reminders, make payments, and more. An efficient and user-friendly mobile application increases client satisfaction (UI UX) and attracts even more users.

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Things to consider when you want to hire iOS developer for your company

Knowledge of the latest mobile trends

Apple continues to dominate the US market in 2019 with a 42% share. Making iOS one of the priorities in development in the USA. A great deal of iOS app (iPhone app) changes occur every year, which is why it is imperative that the mobile engineers (iPhone app developers) you hire are up-to-date and have the precise knowledge of the latest iOS features. It would be a waste of resources if your iOS developers created an iPhone app that is no longer compatible with the latest version of the software.
Bonus points if your experienced iOS developer has quick learning skills. Since there is no slowing down in rollouts of software updates, it is always great to have someone in your development team who can swiftly acquire an understanding of the new features and apply the necessary updates in mobile codes.

Indeed, an experienced iOS developer should possess broad IT and general tech knowledge. However, there are a few absolutely basic skills each iOS developer must have in his resume.

Some of the Recent changes on iOS

Apple releases annually a major software update containing fixes for their iOS and interesting new features for their clients to enjoy (you can find them on Apple app store). But aside from the updates announced during Apple’s event launch, the company also releases minor software changes to keep their devices running smoothly.
Since the best iOS is constantly evolving, recent times brought us some really satisfying features and improvements. Here are key changes in recent iOS development:

1. Dark mode – giving apps beautiful dark color, saving energy, easier on eyes and allowing for scheduling for maximum satisfaction
2. Contacts API – hundreds of new, more specific relationship labels in Contacts help users manage their growing contact lists.
3. Login with Apple – sign in to iOS apps and websites quickly and easily using the Apple ID you already have.
4. Maps – the brand-new map features significantly improved and more realistic details, with the possibility of exploring where you are going before you get there
5. Reminders – the redesigned Reminders app features more powerful and intelligent ways to create, organize, and keep track of your reminders.
6. Keyboard – allowing you to write messages by swiping your finger without removing the finger from the keyboard.
7. Accessibility – introducing new ways to control your phone entirely with voice
8. CarPlay – giving you a single place to keep track of maps, audio controls, and smart Siri suggestions
9. Photos – allowing you to browse your photo library with different levels of curation, photos are intelligently organized, the editing is easier than ever
10. Privacy and Security – letting you totally control your location data, so that no application would be granted access to your location unless you allow it, same goes with Wi-Fi and Bluetooth connections
11. Siri – the voice is now 100 % generated by software making it sound more natural while speaking longer phrases
12. Memoji and messages – grants you an automatically created set of emoji expressions accessible right from the keyboard in iMessage or any other app
13. AirPods –  you can now connect two iPhones and share the audio on both devices

Strong problem-solving skills and “brainpower”

Mobile development has the impression of being less complicated than backend. However, when problems arise, it does not really matter which one is easier to develop—what counts is how quickly your iOS developer is able to fix the issues. Check the applicant: Does he have strong problem-solving skills? Can he provide quick solutions to bug fixes?
In a business where every time spent is critical, having an iOS developer with powerful problem-solving skills and the brainpower for such technicalities can help make or break your projects.
Hire iOS developers who possess exceptional talent only.
The idea is not to test their algorithmic knowledge. That part is easily forgotten after graduation as it is not needed on a daily basis. It is rather to check, how do they think. When given a programming challenge, or a code to debug, can they come up with a solution? How quickly? Do these iOS developers see more than one way of solving the problem? Do they see deeper inclinations of the engineering decision they suggest as a solution? Is the solution optimal in terms of speed/performance and memory efficiency?
After the years in the tech industry, we found that many companies neglect the problem-solving challenge during their recruitment of iOS developers, yet from our experience, it happens to be that the iOS app developers do really well on these kinds of challenges. They magically also tick the majority of all other boxes including good communication skills, organization, extensive knowledge, technical skills, etc. Good app developers shall have them all.
So this is an important step to check even if the app developer applies for a front-end or mobile app development role as a freelance iOS engineer.

Communication and organizational skills

In almost any business, it is constantly essential to have employees with good communication and organizational skills. Find iOS developers who possess such traits. This makes it easier to work on projects since instructions are understood well, concerns are raised clearly, and tasks are handled in an orderly manner. For freelance iOS app developers, this is more significant since the work they do is more on the technical side (with core data) which can easily be mistranslated or misunderstood by people with no technical knowledge.
Even if the iOS developer is really smart, and with years of experience, but struggles to communicate properly within the team, or with the client, that will create a lot of problems during the development phase of the iOS project. You do not want to hire such a software engineer.
With a lot of iOS changes happening in a year, it is very important that the mobile engineer you hire is updated and has the right knowledge with the latest iOS features.

Previous relevant work experience

Hiring someone with previous iOS development experience is always helpful and beneficial for companies. Not only does it give you an idea of an employee’s capabilities, but as well it reduces the learning curve since they already know the demands of the job and iOS app creation.
Perhaps, the more important question that you should be asking in terms of work experience is where the iOS developer has worked previously. Has he been involved in app development before? Has he worked in an international environment? Does he have work experience with fast-paced US-based startups? How about remote works done previously? Has he always worked full time or long term? Was he part of a bigger development team?
Since your company might get clients from all over the world, it can help if you have a mobile iOS developer who has knowledge of how to deal with people and projects from an international environment.
And even more importantly, it is all about the previous experience that is relevant, not just any general mobile or iOS app development experience. Yes, nowadays building a mobile app feels almost like playing with legos, as many things are repetitive and very similar. Yet on the flip side, each project, and in particular each industry is different and has its own characteristics.

Awareness and knowledge of security aspects

Living in the digital age can pose a lot of security issues for clients and business owners. That is the reason why data privacy and security should be a top priority for anyone who is dealing with tech sites and applications. For your software engineer and iOS developer, make sure that they are fully aware and knowledgeable of the security policies to avoid any issues in the future.
Security is not just a field of back-end engineers or DevOps specialists, but also it genuinely helps if the front-end developers (including web and mobile) treat it seriously and have a strong, at the very least – basic, understanding of the subject.
We find that for the enterprise clients really care about security aspects, while startups often neglect it. Of course, it impacts the app development pace, but it should be that the right security foundations are laid out from the very beginning not to take unnecessary risks.

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Check for computer science foundations

Knowledge in the area of computer science is not always necessary when applying for a mobile engineer post. In fact, a foundation in this topic is oftentimes missing for a lot of mobile engineers. However, if you want someone who can complete tasks more smoothly or have a superior understanding of the projects they are dealing with, it is better to get a developer with the said background.
Sadly, nowadays many people are embarking on the technological or software development career journey without previous university foundations in Computer Science. And in some cases it’s fine as long as they make up for it in other areas, yet undoubtedly it helps when an engineer has an overall, broad understanding of the information systems technology and deep knowledge of foundational subjects.

Genuine passion for the job

What are the things that drive and motivate your iOS developer to work in this field? Some companies would no longer ask this question during the hiring process since they only focus on the technicalities and skillsets of applicants tested during the earlier stages.
However, it is valuable to know earlier on if your freelance iOS developer is passionate about the job, since people who actually enjoy what they are doing, tend to be more productive and efficient at work. They’ll do the reading about new trends, and test new technologies and approaches in their spare time which makes them much more knowledgeable, and ultimately relatively better engineers than the ones without passion for tech.

Clear understanding of programming language

Finally, it is really substantial to have experienced developers on the team. Yet the real challenge in the hiring process is evaluating the knowledge of the applicant. One solution is to check his understanding of the tools, in this case, the programming language that he uses. So how would you do it? By asking pretty hard iOS questions during the interview.
Here are some exemplary questions you can use.

1. What will happen, and why, when we execute main.sync on the main thread?

DispatchQueue.main.sync { }
Sync will block the thread from which it is called and not the queue on which it is called. It is the property of DispatchQueue which decides whether the DispatchQueue will wait for the task execution (serial queue) or can run the next task before the current task gets finished (concurrent queue).

2. What is didSet or willSet for a variable and what happens when we assign a value to a variable during initialization?

The willSet and didSet observers of superclass properties are called when a property is set in a subclass initializer after the superclass initializer has been called. They are not called while a class is setting its own properties before the superclass initializer has been called.
willSet is called just before the value is stored and didSet is called immediately after the new value is stored.
willSet and didSet observers are not called when a property is first initialized. They are only called when the property’s value is set outside of an initialization context but you can create your own set-Method and use it within your init-Method:

3. When do you use unowned and when weak in Swift closures?

Use a weak reference whenever it is valid for that reference to become nil at some point during its lifetime. Conversely, use an unowned reference when you know that the reference will never be nil once it has been set during initialization.

4. What are the differences between setNeedsLayout, layoutIfNeeded, and layoutSubviews()?

The method setNeedsLayout for a UIView tells the system that you want it to layout and redraw that view and all of its subviews when it is time for the update cycle. This is an asynchronous activity because the method completes and returns immediately, but it is not until some later time that the layout and redraw actually happens, and you do not know when that update cycle will be.
The method layoutIfNeeded is a synchronous call that tells the system you want a layout and redraw of a view and its subviews, and you want it done immediately without waiting for the update cycle. When the call to this method is complete, the layout has already been adjusted and drawn based on all changes that had been noted prior to the method call.
The default implementation of this layoutSubviews does nothing on iOS 5.1 and earlier. Otherwise, the default implementation uses any constraints you have set to determine the size and position of any subviews. Subclasses can override this method as needed to perform a more precise layout of their subviews.
It is good to know earlier on if your freelance iOS developer is passionate about the job since people who actually enjoy what they are doing tend to be more productive and efficient at work.

The approach

There are two leading approaches to developing mobile applications: Native and Cross-Platform.
The first one is represented by Swift and it stands for developing the app exclusively for a specific platform (iOS in this specific case) with all its features. On the other side, there are Google Flutter and React Native representing the cross-platform approach where, as their names state, the app can be run on different platforms. So without hesitation let us dive right into details.

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Development time

It turns out that cross-platform technologies tend to have lower time-to-market. Not only do they come with better code reusability, but they also provide hot reloading keeping the app running at the time files are edited at runtime.
Following this approach in the case of React Native, the source code is written in JavaScript (or TypeScript, which is a de facto superset of JavaScript with enhanced features). This language is used in various aspects from the browser, mobile applications and even server solutions – this makes it much easier to find a developer and it is also possible to train a current team member who knows JavaScript.
The usability of the code can reach an astonishing scale. In special cases, when the logic used on a mobile application can also be shared in the web version of the application, we can simply use the same portions of code in both places. Without any customization to the platform, just as it is – of course, this will be possible when both solutions are written in JavaScript, and even better when the web version uses the React framework.
Consider this if your project stage allows you to do so!

Potential users

Naturally using native iOS app swift limits the user pool to just the Apple users, as the same app written in React Native or Google Flutter could potentially target up to 50% more potential users. There is no other option to match it but simultaneously developing a separate app for Android.
When you have two native applications, you need to maintain two code bases. This involves a more complex process and more people involved in developing, testing, and deploying changes. In this case, when your goal is to get to your clients as quickly as possible, every minute counts. Cross-platform solutions allow you to develop single source code, in which the solution is usually written only once.
It is much easier to control such a project and also to plan its future development.

Performance

Taking into consideration both CPU and Memory usage, Swift tends to have its edge. Performance tests proved that it uses CPU better than c-p technologies while consuming less memory, although the difference is not significant and for many cases – negligible. Nevertheless, each solution is able to achieve performance (to render at 60 frames per second) equal to that of a native solution. This is confirmed by the use of cross-platform technology by giants such as Uber and Airbnb and the iOS app developers working there.

Cost

Due to the shorter development cycle, React Native and Google Flutter became obviously more cost-efficient. In addition to this, they are relatively easier to learn and debug, making the training part more clear for companies.

Stability

Naturally, Swift being a native language for iOS apps has advantages in terms of native modules and Apple support making it less likely to crash in cases of technology changes. These solutions are developed by major companies in the industry, Facebook is behind React Native and Google is behind Flutter, which confirms that both solutions have and will have long support.
All of the solutions mentioned in the text are prepared to support from small applications to huge scalable corporate applications, providing excellent tools for their implementation.
Swift, Google Flutter and React Native are all very powerful solutions for app development that are being constantly developed to ensure the users can get the best quality products possible based on years of experience. That gives us sufficient certainty that choosing any of these technologies will provide appropriate tools to build great apps with the use of the core data. Eventually, the choice of one over another should be based on the project requirements and the experience of your iOS developers (senior iOS developer vs junior iOS developer).
Notably, there are many well-known companies and iOS developers that utilize either Flutter or React Native (RN) including Alibaba, New York Times, Google Assistant, Groupon, Birch Finance, Uber Eats, Skype for mobile, Facebook, Facebook Ads Manager, Instagram, Pinterest, Google Ads (formerly: Adwords), Tesla or SoundCloud Pulse. So, if you consider a cross-platform solution – you’re in a good company.
As mentioned, one of the platforms where mobile apps are created is Apple’s iOS software platform. If you are one of the companies looking to create an iOS app, it is important to have a mobile engineer with a set of expertise in this operating system in order to have a smooth and successful app development process.

Take away

Starting a mobile application to stay on top of the market is a good start for scaling your business. Outline the goals that you need for your mobile app to ensure that your iOS app is developed to attain your business goal. Ask yourself questions such as, how can it affect the business? Is it aligned with the client’s needs? Design your mobile app with the user first in mind and keep your target audience in mind.
There are a lot more traits out there that you can look for when you want to hire an iOS developer, either for full time or part-time. But in general, it is best to check if a given iOS developer has the knowledge, problem-solving skills, and passion for mobile app development. Check out the blog of DevsData—a software consulting and development company focused on mobile app development – for more hiring tips for web, mobile, back-end, and Big Data, or reach out to us if you have any questions.
This article is also available in German – iOS entwickler.