iOS (formerly iPhone OS) is a mobile operating system created and developed by Apple Inc. exclusively for its hardware. It is the operating system that powers many of the company's mobile devices, including the iPhone and iPod Touch; the term also included the versions running on iPads until the name iPadOS was introduced with version 13 in 2019. It is the world's second-most widely installed mobile operating system, after Android. It is the basis for three other operating systems made by Apple: iPadOS, tvOS, and watchOS. It is proprietary software, although some parts of it are open source under the Apple Public Source License and other licenses.
Most popular language for iOS development is Swift. It is a general-purpose, multi-paradigm, compiled programming language developed by Apple Inc. and the open-source community. First released in 2014, Swift was developed as a replacement for Apple's earlier programming language Objective-C, as Objective-C had been largely unchanged since the early 1980s and lacked modern language features. Swift works with Apple's Cocoa and Cocoa Touch frameworks, and a key aspect of Swift's design was the ability to interoperate with the huge body of existing Objective-C code developed for Apple products over the previous decades. It is built with the open source LLVM compiler framework and has been included in Xcode since version 6, released in 2014. On Apple platforms, it uses the Objective-C runtime library, which allows C, Objective-C, C++ and Swift code to run within one program.
To find a perfect fit for your team, you need to establish who that would be. To give you some examples: a good teammate, excellent level of English, business knowledge, with 3 years of experience, growth-attitude, etc.
To filter the best possible hires, you need a set of steps. We call it a hiring funnel (it’s a lot like a sales funnel). Establish how you want to check your candidate’s skills, way of thinking, culture, and team fit. Prepare questions in advance and take a team member to the interview.
Hiring iOS developers seems difficult because there are a lot of them in the market (but not everyone as experienced and promising as you wish), and there is also high demand. A well-thought-out process is your key to overcome these obstacles.
iOS is so popular, quite a few major business enterprises are well-acquainted with the software. Companies that use iOS include the following:
A clean and expressive language with a simplified syntax and grammar, Swift is easier to read and write. It is very concise, which means less code is required to perform the same task, as compared to Objective-C. Automatic Reference Counting (ARC) does all the work tracking and managing the app’s memory usage, so developers don’t need to spend time and effort doing that manually. Accordingly, it usually takes less time to build iOS apps with Swift. A shining example of this advantage is the Lyft app: The company completely re-wrote its iOS app using Swift. While the old codebase consisted of about 75,000 lines of code, the Swift version recreated the same functionality with less than a third of that. Moreover, the app now featured a new onboarding process: While the old one took more than a month and multiple engineers to implement, the new onboarding with Swift was completed within a week with only one engineer.
In addition to faster development time, you get a product that is future-proof and can be extended with new features as needed. Thus, Swift projects are typically easier to scale. The fact that Apple is more likely to support Swift than Objective-C should also get serious consideration for long-term investment.
As suggested by its name, Swift is made to be… well, swift. With a focus on performance and speed, the language was initially designed to outperform its predecessor. Namely, the initial release claimed a 40 percent increase in performance, as compared to Objective-C.Besides, Swift was built with the LLVM compiler framework, which translates the assembly language to the machine code and optimizes the code, making development faster.Over the years, multiple benchmarks and tests conducted by individual developers have proved that. Moreover, there are many ways to optimize Swift code for even better performance.Another of Swift’s strengths is its safety. Its strong typing system and error handling prevents code crashes and errors in production. Thus, Swift has a shorter feedback loop, allowing you to see the errors in the code instantly and fix them on the fly, greatly reducing the time and effort needed for bug fixing and eliminating the risks of deploying low quality code.
When you build an app, you use a lot of third-party code – reusable and often open source frameworks or libraries compiled into your app’s code. These libraries can be static and dynamic (or shared). You can probably guess that static libraries are locked into code at the time you compiled them, become the part of your executable file, thus increasing its size and load time. They also can’t be automatically updated since they’re stuck in the version you compiled at. Dynamic libraries, on the other hand, exist outside of your code and are uploaded only when needed. Static libraries need to have copies in all files of your program while dynamic ones only need one. Swift first introduced dynamic libraries to iOS when it launched.Since the release version 5.0, standard Swift libraries are integrated into every macOS, iOS, tvOS, and watchOS release. That means any app built on those platforms will be smaller, because these libraries are included. With this advancement, stable application binary interface (ABI) was also released. That allows Apple to provide support of Swift across its platforms.
Objective-C is showing its age and will, eventually, be much less prevalent. But in the here and the now, the two must learn to coexist peacefully.” Accordingly, there are two possible scenarios for using both in the same project: You either add new features in Swift to the existing Objective-C codebase, or use Objective-C elements in your new Swift project.
Either way, Swift language is perfectly compatible with Objective-C and can be used interchangeably within the same project. This is especially useful for large projects that are being extended or updated: You can still add more features with Swift, taking advantage of the existing Objective-C codebase. Thus, the porting process becomes easier and more risk-free.
Swift uses Automatic Reference Counting (ARC) – a technology aimed to add a garbage collector function that wasn’t introduced to iOS before. Languages like Java, C#, and Go use garbage collectors to delete class instances that are no longer used. They are useful to decrease your memory footprint but can add up to 20 percent to CPU. Before ARC, iOS developers had to manage memory manually and constantly manage retain counts of every class. Swift’s ARC determines which instances are no longer in use and gets rid of them on your behalf. It allows you to increase your app’s performance without lagging your memory or CPU.
Indeed, with the strong corporate support from Apple and IBM, Swift has quickly gained one of the most active and vibrant open source communities. The adoption trends, mentioned earlier are a case in point. Besides, Swift is among the top 5 most starred languages on GitHub, coming after Go, TypeScript, and Rust.
While the Swift community is growing fast, it is still significantly smaller as compared to any other open source language. According to the latest StackOverflow Developer Survey, only 5.1 percent of the 83,053 respondents use Swift. It means that if you decide to create your next project using Swift, you might struggle with finding developers that are experienced enough with it.
Largely due to frequent updates, as mentioned above, it is often hard to find the right tools to help with certain tasks. Moreover, the official Apple IDE, XCode, lags in terms of tooling and support for Swift. Developers often report issues with syntax highlighting, autocomplete, refactoring tools, and compilers.
As we mentioned earlier, Swift supports all Apple platforms, as well as Linux and Windows. However, it was originally created and still works best for native iOS development, leaving the cross-platform market to React Native, Xamarin, and Flutter.
You can only use Swift in the apps that target iOS7 and later. That said, Swift can’t be used for legacy projects running on older versions of the operating system. It’s not that significant since only a tiny percent of Apple devices currently run on iOS6 or earlier versions, but you still have to keep that in mind, you know, just in case.
The most obvious alternative to React Native is the separate development for native iOS and Android platforms. As mentioned before, this involves having two teams developing two different apps. This might result in the apps becoming inconsistent, and you won’t be able to reuse code.
If you want your app to really “feel native” or aim at achieving maximum possible performance, native apps are probably still the best way to go. Better documentation and the wider availability of off-the-shelf solutions to popular problems are some other advantages. Be aware of the cost and time implications though.
Currently, the most popular cross-platform alternative to React Native is Flutter, a relatively new mobile application framework developed by Google.It is based on the Dart programming language and takes a different approach to implementing cross-platform features.We found out that it can provide excellent performance and a native look to the apps developed with the help of the framework. As Flutter is quite new, the community is much smaller than when it comes to RN. Also, bear in mind that it is easier for frontend developers to switch to React Native (especially those with some React experience) than to learn a completely new language and framework. Dart might be easier for Java or C# developers, though.
There are many other alternatives for cross-platform mobile development. NativeScript is a framework that allows developing mobile apps using web frameworks like Angular or Vue.js. Xamarin uses the C# language and, like RN, it compiles the code to native controls.Ionic is based on rendering app inside a WebView, which can be slower than other approaches. An interesting alternative for a simple application might be developing a Progressive Web App, a special type of website adapted for mobile and offline use.