Complete hiring guide for Swift developers

Hiring a developer is not something you should do in a rush or alone because there are more aspects to the whole process than you might think. Here, we’ll offer insight into the must-haves, required technical and soft skills, as well as what makes Swift devs experts. We also got you covered withsuggested assessment questions and answers, the benefits of hiring a Swift developer, handling possible hiring challenges successfully, and much more.

About Swift

Swift is a general-purpose, open-source, intuitive programming language with outstanding, robust performance capabilities. Its creator Apple started the Swift development in 2010, led by Chris Lattner, and the main inspiration ideas are based on Rust, Objective-C, Ruby, and C#, among others. The final creation and release of Swift were official in 2014. Then, in 2016, Swift also became available for usage on Linux and Windows.

Swift is generally used for building Mac, iOS, Apple Watch, Apple TV apps, cloud services, and systems programming.

As a programming language, it is interactive, easy to learn, and has a simple yet expressive syntax with modern features. This language allows developers to create fast-functioning software and safe code classes easily.

To this day, Swift is among the more popular languages in programming, showing a wide range of useful and practical features for a quick and easy development process of desktop and mobile apps intended for Apple devices.

Basic requirements and skills of a Swift developer:

A Swift developer must fulfill some basic requirements. Apart from more advanced ones, the following are considered the basic minimum ones to have:

➨ Preferably, a Bachelor's degree in software engineering or computer science ➨ Notable years of experience as a Swift dev

➨ Excellent proficiency in Swift and all it encompasses; The ecosystems Basic syntax, control flow, optionals, and error handling. Classes, inheritance, initialization, and interoperability of Objective-C Xcode – Integrated development environment of Apple

➨ Excellent grasp of RESTful APIs and Cocoa APIs ➨ Solid understanding of UI Focus and UI design and Swift UI ➨ Expertise with OOP (object-oriented programming) ➨ Knowledge of performance characteristics and limits ➨ Expertise in working with embedded databases

Irmin Dzevlan, an experienced iOS developer, defines all of the other essential factors for a great Swift developer:

“For a Swift developer to do their job well, they must also have a good grasp of MVC (model view controller) since it’s widely used in iOS development. Then, also version control tools (like Git) for collaborative development. Also, they must be good at debugging, testing, database management, and app deployment.”

Irmin Dzevlan

As part of the basic requirements and skills, Irmin adds his developer’s point-of-view of what you need to check specifically when you assess and hire a Swift dev:

➨ Checking their portfolio thoroughly – See their previous work to evaluate their expertise better. Always look for iOS apps they built, and review their complexity and functionality.

➨ Asking the right technical questions – All the questions need to be tightly connected to Swift programming; for example, differentiating between structs and classes, defining optionals, generics usage, and similar.

➨ Assigning a complete coding challenge – The core of checking the expertise is the actual coding test. Initially, the dev should have at least coding samples to submit for review. This shows their quality, coding style, and efficient code-writing capability.

➨ Checking their problem-solving skills – This pairs with the coding challenge and the samples mentioned above. You’ll see If the dev knows how to solve a coding problem quickly or how they arrive at solutions.

➨ Checking their communication skills and soft skills – Last but not least, as part of the essentials of a great Swift dev, pay attention to the dev’s overall communication style, soft skills, and whether they are a team player and similar.

Job responsibilities of a Swift developer

There are specific requirements that a Swift developer has to fulfill as part of the work obligations to this role. These typical responsibilities, in general, include:

✅ Designing, developing, and maintaining apps (iOS and OS X)

✅ Monitoring the app integration to the backend

✅ Measuring the app quality, responsiveness, and performance

✅ Recognizing and handling the process bottlenecks

✅ Working on program specifications

✅ Implementing all iOS technologies (widgets, screens, sensors, multi-thread processing)

✅ Locating and fixing bugs

✅ Working on code quality maintenance, as well as automatization

✅ Collaborating with the architect to understand technical solutions well

✅ Communicating and working closely with the DevOps dev team – for new app tests and deployment

✅ Collaborating with other teams for design and features implementation

Required soft skills

A developer is much more than just a person with a good skillset and work experience. What makes a great Swift developer is also work ethic, professional behavior, and overall attitude toward their work environment. Through evaluating the soft skills, recruiters and managers can get a clear picture of the future with this dev as a team member.

Initially, they need to have good presentability and punctuality. This also gives you an idea of their approach to professionalism and responsibilities.

Next, the developer, assuming they work online for an international team, must have good English proficiency and conversational skills. There must be no language barriers between them and the rest of the companyor their clients.

Good work communication is vital for good understanding in the workplace, so curiosity and good listening skills are also must-haves. And the dev also needs to be a great cultural fit because this ensures good team cohesion, collaboration, and pleasant work culture for everyone involved.

Friendly attitude and openness go hand in hand with the traits mentioned above. To nurture a good work relationship, the Swift developer needs to be a team player, open to hearing others’ opinions or requests, and contribute with constructive and genuine ideas and opinions. With this, they’ll also showcase good problem-solving skills because those are an equal part of the communicative and open approach in the workplace.

Required technical skills

A Swift developer must know a few technical skills perfectly for iOS development. Irmin summed up these as the essentials:

“The dev has to master the Swift language above all else, to develop macOS, watchOS, iOS, and tvOS apps - knowing the data types, syntax, control structures, and functions. Then, the iOS frameworks, and thirdly, the OOP (object-oriented programming) concepts such as inheritance, polymorphism, and encapsulation.”

Irmin Dzevlan

An experienced and good Swift developer should also have excellent showcasing of what they know about working with the Swift language. This includes:

➪ Deep understanding of the designs and design patterns of Apple

• All interfaces and principles
• UIKit (frontend framework)
• Apple’s GCD (Grand Central Dispatch)

➪ Knowledge of version control systems

• SVN, Git, and Mercurial

➪ Dimensional reasoning

• Sense of 3D visualization when designing interfaces

➪ Good understanding of multi-threading and memory managing ➪ Expertise in continuous integration ➪ Solid understanding and experience with REST, Protobuf, JSON

➪ Good experience with:

• Core Data – For abstracting details and mapping objects
• Core Animation – infrastructure for manipulating and compositing the content of the app
• Grand Central Dispatch - (API for multiple operations running at the same time, containing libraries, enhancements for systems, and language features too)

Along with the technical skills and must-haves, we also have the tools in Swift that the dev should know how to use and work with. Irmin also listed the following:

➡️ Design patterns – The dev must know the VIPER, MVVM, and MVC well and apply them in their code.

➡️ Debugging tools – There are various debugging tools, but initially, the Xcode ones are a must-know (debugger console, view debugger, breakpoints).

➡️ Unit testing – This includes working with the testing frameworks like Quick and XCTest.

➡️ App architecture – The dev should know how to structure a code nicely and ensure code reusability, maintainability, and scalability.

How would you differentiate between a good and a great Swift developer?

Many qualified Swift developers will be available for work, but you want to hire the best one. Apart from mastering the language and its frameworks, Irmin further sums up how to define the traits of a developer that stands out from the rest:

“A great Swift developer will perfectly fulfill all the technical requirements for the job. More importantly, they will pay outstanding attention to detail and always create easy-to-read code. They will be a fast learner with great problem-solving skills. And, they are informed of latest updates and developments, and they are great communicators too.”

Irmin Dzevlan

Interview questions to assess a Swift developer

When you use Swift-centered assessment questions, you must check the dev’s expertise efficiently and straight to the point. By using defined questions of this type, you quickly recognize the differences between a good and great fit for your team. Here are some questions we recommend.

1. Emphasize the essential and useful features of Swift.

Expected answer: There are many essential features of Swift, but some of them include the following:

• Closures
• Tuples
• No need for semicolons usage
• It is protocol-oriented
• There is closure support
• There are fewer files and less code
• Working with this language goes faster in comparison with other languages
• Very safe
• Simple to use and built-in error handling
• There are designated and convenience initializers (enforced initializers)

2.Elaborate on testing iPhone apps when there is no iOS device available.

Expected answer: In the case of testing Apple apps that were intended for iPhone, of course, we can still do it, but we need to use a specific simulator that we get from Apple and for a Mac system accordingly.

3. Explain the basic data type objects in Swift.

Expected answer: With Swift, we get a set of a few basic data types, and we can use them for numbers, strings, and Boolean values. These are the objects that serve as a fundamental data type:

• String – With these String literals, we can define a specific text that’s surrounded by a double quote enclosing.
• Int – We use the Int for integer value storing.
• Bool – This is used for Bool value storing, and with Swift, there need to be true/false conditions to use this.
• Arrays – A list items collection.
• Double and Float – We use these in Swift when seeing decimal digits.
• Dictionaries – A collection with no particular order in its items, with all items of one type sharing a unique key as a connection.

4. List the Control Transfer Statements and elaborate on their usage.

Expected answer: There are a few types of Swift control statements. Initially, they break down into loops, branches, and transfers. There are five control transfer statements:

• Continue – With this, devs stop a loop execution at its current state. Then the iteration next in line in the loop gets ‘control’ returned to it. This uses the keyword continue in a loop.
• Break – When we see a keyword, this statement will break that current execution. This is used inside a switch or loop block for fast, early exiting.
• Fallthrough – When we make a match or find the first match, the ‘switch’ statement runs the case that’s next in line. It means we execute code for a specific case and end it with the same statement, switch.
• Return – Used for returning a function. An efficient, simple keyword for returning values is used when we’re inside some function.
• Throw – Sometimes functions can make errors, but in this case, we make a ‘throwing function’ out of the current function by using the keyword throw. Here, we place the error that happened earlier.

5. Compare the identity and equality operators.

Expected answer: An equality operator == is used when we compare two values, and we need to review if those values are equal and identical. Then we have the identity operator === used to see if both references we have direct toward one memory address or instance. So, if we compare two references with different instances of objects, the identity operator will always pop up as false. It doesn’t matter that the instances share an identical value in this case.

6. Explain the needed action for “circular reference.”

Expected answer: We get a circular reference when we have two instances with a significantly solid mutual reference. This is the main reason for so-called ‘memory leaks’ when both instances cannot be delocated. Instances’ delocation is not possible because the instances help each other to stay active and to stay alive. What we can do, though, is use ‘weak’ or ‘unowned’ references in place of the strong ones. By this, we quickly solve a circular reference successfully.

7. Describe the optional chaining in Swift.

Expected answer: When we invoke properties, subscripts, and methods on an optional, that is called optional chaining. We can extract a sequence value with this step if we have an optional values sequence. To return a value, we need to call a method, subscript, or a property of the optional, but only if the optional contains a value already. If a property returns as ‘nil’, it means that the optional itself is ‘nil’ when we call the method, subscript, or property.

8. Elaborate on “inheritance” and its benefits.

Expected answer: When methods, properties, and various characteristics are inherited from one class to another, that’s called “inheritance” in Swift. The class that “lends” those properties is called ‘super class’ or ‘parent’, and the class that inherits them is called ‘child’ or “sub-class.”

The benefits of inheritance are:

• Smaller source code size
• Better code readability
• Reusing of code
• Easy division splitting of code (if we want to get ‘parent’ and ‘child’ separate classes)
• Better extensibility of code
• No code-redundancy

9. Explain the connection between NSUserDefault and Core Data.

Expected answer: When we need to store app settings and preferences, we use NSUserDefaults. It’s important to remember not to store user data or other critical data in this case. Most frequently, we use the NSUserDefaults to store some flags or even small projects, but we always avoid using it when working with image caching or big data storage.

The fully-fledged and persistent framework is called CoreData, and it’s excellent for transactions of large-size data. When we need to make an entity-attribute model and store user data, we use the CoreData, because it’s perfect for large-size projects, unlike NSUserDefaults.

10. Define Facade Design Pattern.

Expected answer: A system complexity, simplified and fit for structural design pattern, is contained in the facade pattern. While this design doesn’t show how it works precisely, it showcases a user-friendly interface and gives system access to the client programs. So, to call user-defined functions and system-related classes through delegates, we must first use the Facade Design Pattern to get a single class or FACADE that contains all these mentioned delegates.

Why do you need to hire a Swift developer?

It’s important to define why you need to hire a Swift developer overall. What is the need for this hiring process?

What does this mean for the app development processes in the long run, and what do you get out of it? Let’s see.

➨ Quick app development – Swift uses a very straightforward and simple grammar and syntax, creating fewer requirements for a particular task-specific code. The work is regulated nicely by ARC (Automatic Reference Counting) regulates the work nicely, and we get a good, controlled overview of the memory and its usage. All in all, this makes devs develop much faster too.

➨ Simple to implement – Anyone proficient in development can easily download Siwft and use it for their iOS app development, mainly because it’s open-source. Still, it’s much better to get a professional Swift developer with extensive expertise in iOS precisely to get the job done perfectly and quickly too.

➨ Viable performance – If we want to get code from a language, we translate the language quickly with the help of the LLVM infrastructure (library for machine-native code creation). All code errors will be quickly recognized and resolved, and there is no risk of the code crashing at this point too. Another good thing is that there is much less risk of subpar code deployment.

➨ Improved app salability – With the right Swift devs, you will have a highly-functional app that works with the speed of light. Whenever the dev needs to add new things to the app or certain features, they can do it easily and efficiently, ensuring that the app functions perfectly at all times. After all, for the app to sell and users to be satisfied, it has to be kept perfectly working, without any exception.

➨ Better memory management – The ARC has a practical function of ‘garbage collecting’, removing and erasing unnecessary instances. This gives us a faster development process, with just a little memory used overall.

➨ Reusing code – We can reuse written code with Swift, both in the back and front end, making the process run smoothly and quickly. This also makes us save money in the long run, taking all things into account.

➨ Reduced volume and size – Apps we create with Swift will be significantly smaller overall because this language already contains all the crucial libraries. Because of the secure Application Binary Interface (ABI), all Apple platforms support this language.

What do you get when you hire a Swift developer and use Swift for your business?

When you rely on professional Swift developers that are vetted and have complete expertise in iOS app creation, you get:

✅ High-performance and responsive mobile apps

✅ Innovative CI/CD solutions

✅ Easy APIs access

✅ Excellent enterprise app development

✅ Easy APIs access

✅ Simple capabilities incorporating iOS device data-communicating

✅ Beautifully designed UIs

✅ Outstanding app security

✅ Excellent UX, adaptable performance, and clean code

✅ Simplified debugging with the help of XCode (Apple IDE - Integrated Development Environment)

Overall there are numerous benefits from working with Swift, both for the developer who uses this language and for the business that utilizes it in their work, and Irmin mentions a few:

1. High performance

Since this is a compiled language, it can run much faster than others, like JavaScript. The dev efficiently optimizes the code and compiler level.

2. Simplicity

Swift is easier to learn and simpler to use in practical matters than other languages. The syntax is easy to understand, and the features are all user-friendly. It is fantastic, especially for those new to mobile development.

3. Fast development

Since the syntax of Swift is modern and clean, the coding process moves much quicker than expected and more efficiently. The dev can catch any error on time and fix any issues early.

4. Open source

Swift is free to use, and it’s excellent that devs can also contribute with their expertise to developing this language. This way, big companies save a lot of money that would be spent on licensing fees otherwise. It’s a constantly-evolving language, which is beneficial for everyone.

5. Interoperability

There is an easy integration between Swift and the Objective-C code, so if the dev needs to use both languages for one project, they can do it easily. This is best for companies that already have iOS apps built on Objective-C.

6. Safety

Swift's optionals system and type safety prevent errors, crashes, or unexpected app behaviors.

Popular brand names that rely on using Swift

Swift is a reliable programming language of choice for the following renowned brands:

1. Apple
2. Coursera
3. 9GAG
4. LinkedIn
5. Meta/Facebook
6. Robinhood
7. Uber
8. Lyft
9. Asana
10. IBM
11. Square
12. Uber

Different industries and applications of Swift

The Swift language is used in many versatile industries, making it valuable for various companies and businesses. Some of them with particular needs and context for Swift are:

Mobile app development

For any iOS mobile app, Swift is the primary choice, especially since many businesses require iOS apps for interactions with customers.

Gaming

Games for iOS devices are also built with Swift, which is very important when mobile gaming is becoming more popular than ever. There is a vast need for Swift devs that can create high-quality, engaging gaming experiences.

Healthcare

In the healthcare industry, there have been a lot of adaptations to using mobile technology, so for managing patient data, monitoring health, and providing telemedicine services, Swift is a great language to use.

Education

Swift is also an excellent language for the development of educational apps for iOS devices, and these apps include study aids, learning apps, and educational games too.

Finance

Every financial institution also needs reliable and secure apps for managing investments, transactions, and customer data. Financial apps built with Swift provide strong type safety without risks of security vulnerabilities or errors.

E-commerce

Online businesses require using of e-commerce apps for better safety and speed of the apps. Through quality and secure apps, companies engage with their customers much better and faster in the long run.

Social networking

Now more than ever, social apps are thriving and are incredibly popular, perhaps more than anything else. A skilled Swift dev will be able to create engaging experiences that connect users with their social circles.

Possible challenges during the hiring of a Swift developer

Before hiring a Swift developer, you must also know potential challenges during the search and hiring process.

First, many unqualified developers may be in the pool of job seekers. It could be a vast pool of many who’d like to work in Swift development, but they could lack the expertise needed and offer just a subpar knowledge of Swift.

Along this, there is another scenario risk: a small number of highly qualified Swift developers. This could slow down your dev search significantly and, thus, prolong the whole hiring process, which, when prolonged, costs more money and time too. If this is the case, it’s not a surprise that a limited number of qualified devs will also require a larger salary since they are in high demand among many others with less expertise and qualifications.

Then there are also the recruitment costs. If you do the whole process alone or with in-house support, it would take some time, probably months, to finish it, and it doesn’t necessarily mean you will complete it successfully. The longer you search for the perfect Swift dev, the more your recruitment costs increase.

And speaking of costs, another challenge is the competitors and the salaries they offer. Try to browse the job platforms and general surveys about salaries offered for that position to see whether you are in a similar range or too different from the competitors. They might offer some perks and benefits or rely on a very high salary – whatever the case may be, stay informed to plan your hiring process as best as possible.

A great, all-encompassing solution to these challenges would be to rely on distributed teams and staffing hiring models. At the same time, you won’t need to overthink where are the best devs or if you’d wait for months before you find them. You won’t need to worry about competitors and recruitment issues down the road too.