Mobile app programming languages explained

13 min read
March 7, 2021

With revenues from mobile apps projected to reach $935.2 billion by 2023, there’s no better time to start your big app project. To pull it off, however, you’ll need to be prepared for the many inevitable mistakes that will come your way. 

One of the most crucial decisions you’ll have to make is which app programming language to use. 

Choosing the right one can help you develop and scale even the most complex apps much more quickly with less money and effort.

To help you decide, we’ll cover the most common mobile programming languages and when you should use each.

Programming Languages for iOS Apps

When considering iOS programming languages, there are only two you’ll ever choose from: Swift and Objective-C. 

Other hybrid tools or frameworks, like React Native, convert their code into either of these two.

Let’s start with the most popular app programming language for iOS right now — Swift.


Swift is a beginner-friendly yet powerful iOS programming language designed by Apple to replace Objective C for its native app development

And it’s slowly getting there — as of February 2021, Swift ranks 15th in the TIOBE Index, five spots ahead of Objective-C. 

frame 5

It’s very popular in the community, with more than 70% of hobbyist programmers and 42% of professional developers claiming to use Swift.

It’s not hard to justify Swift’s rising popularity. 

Compared to Objective-C, Swift has better speed, performance, and memory-handling features

It’s easy to learn and read with a syntax that closely resembles human language

You’ll also have less chance of writing buggy code with Swift thanks to its safety and error-handling mechanisms that can catch common programming errors.

Swift key features

Loved more than Objective C in iOS development

Better speed and performance than Objective C

Easy to learn and read language

Error handling mechanisms

Capable for creating complex apps

For these reasons, Swift is best for beginner programmers or developers who want to transition into iOS development. 

Despite being easy to use, Swift is more than capable of creating complex projects. Real-world examples that prove this point include Linkedin, Uber, and Lyft.

The only main drawback of Swift is its relatively young age. 

There are still unresolved issues, such as poor backward compatibility with previous Swift versions and lack of third-party tools. 

Nevertheless, with the announcement of Swift 6, Apple is further cementing Swift as the next-generation iOS language.

Objective C

Objective-C is the original iOS language, used since the very first days of Apple app development. 

The language is a superset of C, inheriting many of its syntax and coding rules while adding modern object-oriented programming mechanisms.

Because of the longevity of Objective-C, it’s a relatively stable and reliable programming language. 

It has a strong community with an extensive repository of libraries, documentation, and tutorials to help you in any situation.

Objective C key features

Original iOS language

Stable and reliable programming language

Strong developer community and documentation

Has complex syntax that is more difficult to learn

However, there is a legit reason why Swift is quickly overtaking Objective-C. The latter has a steep learning curve, with complex syntax rules and memory management, that can deter new developers from learning the language.

Still, despite adoption slowing down, Objective-C isn’t going away anytime soon. 

All of Apple’s frameworks, including Cocoa, are all written in this language. Many apps in the Apple app store, such as Instagram, Pinterest, and Slack, still use it. 

Moreover, even those that switched to Swift, like Uber, still maintain a portion of their code in Objective-C.

You should use Objective-C if you’re maintaining or updating legacy apps written in the language.

That’s because it would be more time-consuming and costly to learn and transition into Swift, no matter how easy it is to use. 

Also, while Swift is faster, Objective-C is still a powerful and capable language on its own.

Programming Languages for Android Apps

Much like iOS, there are only two officially-recognized programming languages in Android development – Java and Kotlin. 

Frame 6289

However, thanks to the open-source nature of Android, you can also incorporate other languages like C/C++, but on a limited scale.


Java is the first object-oriented programming language officially recognized by Google for Android app development. It’s also one of the most well-loved by developers worldwide

The language is stable and reliable, with a long history of mobile development since the early 2000s. That means developers can access plenty of resources, vast third-party libraries, and experience from other Java programmers. 

Java itself is robust and secure, part of the reason why it’s a popular platform for enterprise software.

Still, the big reason to still use Java is its tight integration with Android. In fact, parts of that OS, like the UI and specific core libraries, are written in the language. 

Java key features

Robust and secure – great for enterprise software

Stable and reliable language

Loved by developers

Object-oriented programming language

Harder to debug

Because of this, Java Android apps tend to have better compatibility, performance, and API integration than other languages.

However, Java still presents several disadvantages to developers. 

The language tends to be verbose as a result of its human-readable quality. Hence, programmers end up writing more code that can be harder to debug. 

Also, while Java is a common language taught in introductory programming courses, it still carries a steep learning curve. 

Addressing these limitations is what spurred the development of another Android programming language – Kotlin.


Kotlin is an open-source programming language that runs on the Java Virtual Machine (JVM). 

What started as an improvement over many of Java’s limitations is now Google’s preferred language for Android development, further cementing Kotlin as a viable Java alternative.

One area where Kotlin is a step-up from Java is the latter’s tendency to write boilerplate – or unnecessarily long – code. 

Kotlin is both expressive and concise, allowing developers to produce shorter, easier-to-maintain code.

Null pointers, one of the biggest causes of app crashes in Java, are largely eliminated with Kotlin. This leads to fewer crashes when using the language, an experience Google had when they decided to incorporate Kotlin into their Google Home app.

Pro tip: try the Shake app to manage app crashes and fix bugs faster.

Kotlin has a near 100% compatibility with Java since they both run on the JVM. 

They can share the same tools and libraries, making it safe and easy to transition your project from Java to Kotlin and still maintain functionality. You can even mix Kotlin and Java modules in a single app.

With the direction Google is taking with Kotlin, it’s a worthwhile language for future-proofing your next project. 

The only drawbacks include a lack of a large community (which Java has) and the learning curve involved for Java developers.


C/C++ is one of the most powerful programming languages ever made, used in everything from operating systems to high-performance 3D applications. 

To use C/C++ code, you need to compile it into a native library using the Native Development Kit (NDK). 

C++ key features

One of the most powerful programming languages

Needs to use Native Development Kit (NDK)

Great for games or simulations due to its faster performance

There are plenty of C++ libraries

This, in turn, allows your Java code to access C/C++ functions from that native library.

Because of the added complexity, C/C++ code tends to be harder to implement in Android apps. So what’s the point of using it then?

The biggest use case for C/C++ is if you want faster performance for computationally-intensive applications like games or simulations. C/C++ is almost incomparable in terms of execution speed and efficiency. 

It’s also closer to the underlying hardware than other languages, giving you complete control over device-specific functions and resources.

The other reason is to use an existing C/C++ code you or other developers have written with your Android app. There are plenty of C/C++ libraries out there, giving you access to functions beyond what the standard Android packages can do.

Still, unless you’re writing high-performance Android apps where latency is critical, it’s best to stick with Java or Kotlin over C/C++.

Programming Frameworks for Hybrid Apps

Hybrid programming languages solve the biggest problem with cross-platform apps: maintaining multiple codebases for each OS. 

Frame 6290

With hybrid solutions, you deal with only one source code, which automatically gets converted into OS-specific apps.

React Native

React Native (RN) is a robust mobile development framework based on Javascript for creating Android and iOS apps rapidly and efficiently. It’s one of the most popular cross-platform development tools used by 42% of developers worldwide

Big-name projects that use RN include Shopify, Walmart, and Discord.

RN works by taking code written in Javascript and compiling it into native OS code, allowing developers to reuse up to 90% of the codebase across platforms for better consistency.

Compared to hybrid solutions like WebView, React Native has near-native app speed and performance. 

React Native key features

One of the most popular cross-platform development tools

Near-native app speed and performance

Not as fast as a true native app

No need to maintain multiple codebases

It also has built-in support for Flipper (a debugging platform), giving app developers a suite of debugging and testing tools.

However, React Native still isn’t as fast as a true native app

It also can’t keep up with iOS and Android SDK updates as they come, which slows down the adoption of new OS features.

Nevertheless, RN is still the best tool for cross-platform app development. 

It simplifies your project by requiring you only to use JavaScript, one of the most popular and widely used languages today

You also don’t need to maintain multiple codebases. If you want to update your app across all platforms, you just need to change the original RN code.


Flutter is Google’s answer to React Native — a cross-platform app development kit using a proprietary programming language called Dart. 

It’s a framework that’s quickly gaining popularity, with over 12,000 apps, including Google and Alibaba, using the platform.

Compared to React Native, Flutter offers several distinct improvements. The most crucial is that it draws UI components directly on each native OS, unlike RN or Xamarin that relies on platform-specific UI libraries. 

This means that your app’s look on iOS will be identical on any other Android phone. 

Flutter key features

Draws UI components directly on each native OS

Allows for faster app performance

Supports hot reloading

The average size of a Flutter APK is bigger than others

Great for building UI-heavy applications

The other is that Flutter is compiled ahead of time instead of using a runtime environment like RN. That leads to faster app performance overall.

Other than that, Flutter and React Native both share similar features that make cross-platform development easier. They both support hot reloading, which allows the UI to update instantly without needing to rebuild the code. 

Furthermore, the native Flutter language, Dart, is as easy to use as RN’s JavaScript.

However, be aware of Flutter’s main flaw — file sizes. 

As this analysis illustrates, the average size of a Flutter APK is among the biggest compared to RN, Java, and Kotlin apps. 

Also, because Flutter draws its UI components from scratch, apps will not achieve a true “native” look.

Nevertheless, Flutter is a fantastic platform for building UI-heavy applications across devices with greater visual consistency.


Xamarin is a Microsoft-owned cross-platform development tool tightly integrated into the .NET framework and Visual Studio IDE. 

It allows you to create apps using C# and deploy them across platforms, including iOS, Android, and Windows.

The main draw of using Xamarin is if you’re a .NET developer and want to bring your project to mobile. Since you’d be already familiar with both C# and Visual Studio, there’s no need to learn a new language or switch to a new IDE

This saves you a lot of development time and cost.

Plus, thanks to Xamarin’s tight integration with the .NET framework, you can bring the robust libraries, debugging tools, and UI design features of the .NET development environment into your app projects.

Xamarin gives developers the flexibility to use either the Forms technology to deploy one codebase to multiple platforms or Xamarin Native to design OS-specific apps separately.

Both approaches allow you to reuse anywhere from 70% to 95% of the codebase.

However, Xamarin has several limitations that make it fall behind React Native and Flutter. 

It’s more challenging to create apps with complicated graphics and animation effects in Xamarin, making it unsuitable for most gaming projects. 

File sizes also tend to be twice as big as native apps.

Nevertheless, if you’re coming from .NET, Xamarin is your fastest route to mobile app development. Companies that use Xamarin include BBVA, UPS, and Alaska Airlines.


Ionic is an open-source tool that focuses on creating cross-platform UI components quickly and easily. 

It does this by leveraging front-end web design technologies like HTML5, CSS, React, and Angular to render apps on a browser called a WebView.

This reliance on universal web platforms allows web developers to use their existing skillset to build cross-OS applications, making it easier than ever to transition to mobile.

Small companies and startups can drastically reduce development costs by leveraging existing talent while bringing their apps to market faster.

Ionic includes a wealth of UI components, including themes, fonts, and interactive elements, that you can use to create highly responsive app interfaces.

It also has several plugins available that give you access to hardware-specific capabilities.

Ionic key features

WebView-based hybrid app platform

Includes a wealth of UI components

Good for basic functions and for creating simple app projects

However, since Ionic is a WebView-based hybrid app platform, it can’t compete with the performance of native apps or cross-platform tools like RN and Flutter that mimic native capabilities. 

Any functionality beyond the basics, such as 3D animation or AR, can cause considerable slowdown. Standard features of RN and Flutter like hot reloading are also absent in Ionic.

But if you have a web developer team, Ionic is the best and easiest way to create simple app projects.

To date, Ionic has been used in over 5 million apps and backed by a passionate community. Some examples of Ionic projects include MarketWatch, Target, and NASA. 


Picking a suitable programming language is a critical step in any mobile development project – one that will shape countless aspects of your app.

But as this article shows, the choice isn’t really that difficult. 

At most, you’ll only ever need to choose between two or three options, depending on your platform.

As long as you understand each language’s nuances and how they fit into your app’s requirements, you can easily make the right decision.

If you want to know more about app development, check out our step-by-step guide on creating an app.

Written by

Mario Zderic

Co-founder and CTO

Mario makes every project run smoothly. A firm believer that people are DECODE’s most vital resource, he naturally grew into the role of People Operations Manager. Now, his encyclopaedic knowledge of every DECODEr’s role, and his expertise in all things tech, powers him to manage his huge range of responsibilities as COO. Part developer, and seemingly part therapist, Mario is always calm under pressure, which helps to maintain the office’s stress-free vibe. In fact, sitting and thinking is his main hobby. What’s more Zen than that?

Related articles