React Native vs Kotlin: Full Guide for Android App Development

React Native and Kotlin are two of the most popular ways to develop Android apps. Both allow you to build fast, performant, feature-rich applications, with modern, readable syntaxes that are easy to use.

So which one should you choose for your project? Read on and we’ll break down React Native and Kotlin in detail, and explain why you should choose one over the other.

What is React Native?

React Native is an open-source JavaScript framework, developed by Facebook and released in 2015.

Its tagline is “Learn once, write anywhere.” The idea is to allow developers to use JavaScript to write applications for iOS and Android devices, eliminating the need for multiple codebases in multiple programming languages.

React Native apps are able to deliver like-native performance; not on the same level as a fully native app, but the framework provides native modules and native UI components that replicate, to a degree, the look and feel of a native app.

The framework has a large and active community, is actively maintained by Meta, and is used in many high-profile mobile apps, including Facebook, Skype and Instagram.

What is Kotlin?

Kotlin is a native programming language for the Android operating system. It’s open-source, developed and maintained by JetBrains, released in 2016.

Kotlin is currently the official language for Android app development. It’s a statically typed, object-oriented, functional programming language, with a modern, concise and readable syntax.

Kotlin was developed to improve on a number of aspects from Java (not to be confused with JavaScript), which used to be the preferred language for Android developers.

Many consider Kotlin to be a simpler and more modern language than Java. The two languages are, however, interoperable, meaning Java code and Kotlin code can be used together.

Kotlin’s ecosystem is steadily growing, with support from Google, and large companies such as McDonalds, Adobe, Forbes and Philips all using it in their apps.

Key Differences Between React Native and Kotlin

We know a little bit about React Native and Kotlin now, so let’s dig deeper into the differences between these two mobile app development frameworks.

Cross-Platform vs Android

Probably the most notable difference is that React Native is a cross-platform development framework, which can be used to build apps for both Android and iOS devices.

Cross-platform frameworks cut down development time and effort, as well as maintenance load, by requiring less duplication of work and a smaller team to build and maintain apps on both platforms.

Kotlin, on the other hand, is primarily a language for Android development. Though developers are able to use Kotlin to build apps for other platforms now through Kotlin Multiplatform (which we’ll get into a little later), its bread and butter is the Android OS.

Performance

For the convenience of cross-platform, you’ll need to make sacrifices, and one such sacrifice is performance.

It’s not that React Native apps perform poorly, but the level of performance can’t match that of a native language like Kotlin.

For simple apps, there might not be much of a noticeable difference, but the more complex your app, or the more you want to integrate with native device functionality, the more Kotlin will pull ahead.

Language & Syntax

React Native is essentially React for mobile apps, which in turn is a UI library for JavaScript. So JavaScript is the actual language behind your app, and the syntax will be familiar for anyone with previous experience with JS.

Kotlin is itself a programming language, rather than a framework (as React Native is). The syntax, however, is fairly straightforward, with an object-oriented style similar to JavaScript, Python and other popular languages.

Hot Reloading

React Native supports hot reloading, which means developers are able to see code changes in real time, without reloading the app. This is a significant advantage for front-end developers in particular, as it allows much faster iteration and development.

Kotlin does not come with hot reloading support, which may make the development experience a little more tedious.

Ecosystem

React Native has a more extensive ecosystem. It has a large community of developers, with extensive documentation and resources available, including a wide array of third-party libraries.

Kotlin’s ecosystem is not lacking, but it’s not quite on the same level as React Native’s.

Popularity

React Native is overall more popular than Kotlin, though ultimately this is a matter of preference for each developer.

React Native has 116k stars, 23.9k forks on Github, compared to 47.5k stars and 5.6k forks for Kotlin.

Google Trends shows a consistently higher number of people interested in React Native, over the last five years.

We can also gauge popularity by the demand for developers in each field. Indeed currently lists 846 React Native job openings in the US, versus 648 for Kotlin.

On LinkedIn jobs, a US search comes up with 6,107 results for React Native jobs, and 3,833 results for Kotlin.

So while it’s hard to say definitively that React Native is more popular, it does seem to be a programming speciality that is in higher demand.

Learning Curve

React Native will have a shorter learning curve for most. Since it’s based on JavaScript, one of the world’s most popular and widely used programming languages, the average developer will be able to pick up React Native without much trouble.

Kotlin doesn’t have a massive learning curve itself, and anyone with experience in Java will find it quick and easy to learn Kotlin.

For someone coming in without prior knowledge of either Java or JavaScript, the learning curve for React Native vs Kotlin should be fairly even, though a slight edge still for React Native.

Development Cost and Time

To develop apps for Android only, there’s unlikely to be a major difference in cost and time investment between React Native and Kotlin.

Development outsourcing company YouTeam puts the average cost of a React Native developer slightly higher than Kotlin.

Their data has the average cost of an offshore React Native developer at $50.10 per hour or $8,016 per month.

Kotlin developers, in comparison, cost an average of $49.49 per hour or $7918.40 per month.

Yet it may be easier to find React Native developers, and with a larger talent pool, it may be cheaper to find a viable option.

In terms of time, the edge might go slightly to React Native, as its support for hot reloading makes iteration quicker and the syntax is generally a bit simpler, though the ability to write native code with Kotlin may make it faster, as there will be fewer kinks to iron out before shipping the final build.

The question changes if you’re planning to launch both iOS and Android apps. The ability to use React Native for both cuts down development time (and as a result, cost) a lot.

If you were to use Kotlin for Android and Swift, for example, for iOS, that would add a lot to the final cost.

However, you may be able to achieve a similar result in terms of using one framework and one codebase for both iOS and Android if you use Kotlin Multiplatform, which we’ll expand on shortly.

Is React Native or Kotlin Better?

So let’s settle it - should you use React Native or Kotlin?

There’s no right or wrong answer here, and both options have their upsides and downsides. React Native is more efficient and more accessible, while Kotlin provides better native performance.

Below, we outline the situations when you’d want to choose one or the other.

Why You Should Choose React Native

In general, React Native is a better choice if you’re looking to build cross-platform mobile apps.

Go with React Native if:

• You or your team have experience working with JavaScript or JavaScript frameworks like React.
• You want to launch apps for iOS as well as Android.
• You prefer the development experience of a framework that supports hot reloading, and having access to a wider range of resources, libraries and developers.

Why You Should Choose Kotlin

Native app development is the choice if you’re only looking to build an Android app, or if native integration and performance is a priority.

Choose Kotlin if:

• You don’t need an iPhone app.
• You need a high level of integration with device features, such as camera, GPS, biometric scanners, etc.
• Native performance is a priority.
• You have prior experience with Java, or prefer working with Java-based languages over JavaScript.

React Native vs Kotlin Multiplatform

Released in 2017, Kotlin Multiplatform allows you to write and deploy code across multiple platforms, including Android, iOS, web and desktop.

You can share part of your code, or even your entire code, for multiple apps, making Kotlin Multiplatform a much closer competitor to React Native.

McDonalds, 9GAG, Netflix, Philips and VMware are a few examples of high-profile companies using Kotlin Multiplatform for cross-platform apps.

So is it worth using Kotlin Multiplatform over React Native, if it eliminates one of React Native’s biggest advantages (cross-platform compatibility)?

Perhaps. Here are a few points to consider regarding Kotlin Multiplatform and how it compares to React Native:

• Syntax is still Java-based. So there’s the same decision to make on whether you want to use a framework based on Java or JavaScript. For many, a JavaScript-based framework is preferable.
• Kotlin Multiplatform has the potential to ship to more platforms, with compatibility for web and desktop apps as well as mobile.
• Kotlin Multiplatform utilizes native components and APIs, which may mean better performance.
• It is still in a somewhat experimental state, with a limited number of libraries available.
• Development may not be as quick as with React Native.
• Smaller pool of skilled developers to choose from with experience in Kotlin Multiplatform.

Ultimately, Kotlin Multiplatform is still quite new, despite being launched not long after the main Kotlin language.

In this survey on the most popular cross-platform mobile frameworks, just 3% of the respondents had used Kotlin Mutliplatform. In comparison, 32% responded for React Native, making it the second most popular framework (behind Flutter).

Kotlin Multiplatform may be a better alternative to React Native, but it’s also untested and unrefined, so those wanting a safer option may want to go with React Native instead, or one of the alternatives below.

Alternatives to React Native or Kotlin

React Native and Kotlin are not the only games in town.

Alternative cross-platform frameworks include:

• Flutter
• Ionic
• NativeScript
• .NET MAUI (formerly Xamarin)

While other native mobile programming languages include:

• Java (for Android)
• Swift (for iOS)
• Objective-C (for iOS)

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