What is cross-platform mobile development?
Nowadays, many companies are facing the challenge of needing to build mobile apps for multiple platforms, specifically for both Android and iOS. This is why cross-platform mobile development solutions have emerged as one of the most popular software development trends.
According to Statista, there were 3.55 million mobile apps available on the Google Play Store and 1.6 million apps on the App Store in the third quarter of 2022, with Android and iOS together now accounting for 99% of the worldwide mobile operating system market.
How do you go about creating a mobile app that can reach Android and iOS audiences? In this article, you will find out why more and more mobile engineers are choosing a cross-platform, or multiplatform, mobile development approach.
Cross-platform mobile development: definition and solutions
Multiplatform mobile development is an approach that allows you to build a single mobile application that runs smoothly on several operating systems. In cross-platform apps, some or even all of the source code can be shared. This means that developers can create and deploy mobile assets that work on both Android and iOS without having to recode them for each individual platform.
Different approaches to mobile app development
There are four main ways to create an application for both Android and iOS.
1. Separate native apps for each operating system
When creating native apps, developers build an application for a particular operating system and rely on tools and programming languages designed specifically for one platform: Kotlin or Java for Android, Objective-C or Swift for iOS.
These tools and languages give you access to the features and capabilities of a given OS and allow you to craft responsive apps with intuitive interfaces. But if you want to reach both Android and iOS audiences, you will have to create separate applications, and that takes a lot of time and effort.
2. Progressive web apps (PWAs)
Progressive web apps combine the features of mobile apps with solutions used in web development. Roughly speaking, they offer a mix of a website and a mobile application. Developers build PWAs using web technologies, such as JavaScript, HTML, CSS, and WebAssembly.
Web applications do not require separate bundling or distribution and can be published online. They are accessible via the browser on your computer, smartphone, and tablet, and don't need to be installed via Google Play or the App Store.
The drawback here is that users cannot utilize all of their device's functionality while using the app, such as contacts, calendars, the phone, and other assets, which results in a limited user experience. In terms of app performance, native apps have the lead.
3. Cross-platform apps
As mentioned earlier, multiplatform apps are designed to run identically on different mobile platforms. Cross-platform frameworks allow you to write shareable and reusable code for the purpose of developing such apps.
This approach has several benefits, such as efficiency with respect to both time and cost. We'll take a closer look at the pros and cons of cross-platform mobile development in a later section.
4. Hybrid apps
When browsing websites and forums, you may notice that some people use the terms "cross-platform mobile development" and "hybrid mobile development" interchangeably. Doing so, however, is not entirely accurate.
When it comes to cross-platform apps, mobile engineers can write code once and then reuse it on different platforms. Hybrid app development, on the other hand, is an approach that combines native and web technologies. It requires you to embed code written in a web development language, like HTML, CSS, or JavaScript, into a native app. You can do this with the help of frameworks, such as Ionic Capacitor and Apache Cordova, using additional plugins to access the native functionalities of platforms.
The only similarity between cross-platform and hybrid development is code shareability. In terms of performance, hybrid applications are not on par with native apps. Because hybrid apps deploy a single codebase, some features are specific to a particular OS and don't function well on others.
Native or cross-platform app development: a longstanding debate
The debate around native and cross-platform development remains unresolved in the tech community. Both technologies are in constant evolution and come with their own benefits and limitations.
Some experts still prefer native mobile development over multiplatform solutions, identifying the stronger performance and better user experience of native apps as some of the most important benefits.
However, many modern businesses need to reduce the time to market and the cost of per-platform development while still aiming to have a presence both on Android and iOS. This is where cross-platform development technologies like Kotlin Multiplatform (KMP) can help, as David Henry and Mel Yahya, senior software engineers at Netflix, note:
Is cross-platform mobile development right for you?
Choosing a mobile development approach that is right for you depends on many factors, like business requirements, objectives, and tasks. Like any other solution, cross-platform mobile development has its pros and cons.
Benefits of cross-platform development
There are plenty of reasons businesses choose this approach over other options.
1. Reusable code
With cross-platform programming, mobile engineers don't need to write new code for every operating system. Using a single codebase allows developers to cut down on time spent doing repetitive tasks, such as API calls, data storage, data serialization, and analytics implementation.
Technologies like Kotlin Multiplatform allow you to implement the data, business, and presentation layers of your app just once. Alternatively, you can adopt KMP gradually: Choose a piece of logic that changes frequently and usually goes out of sync, such as data validation, filtering, or sorting; make it cross-platform; and then connect it to your project as a microlibrary.
At JetBrains, we regularly conduct Kotlin Multiplatform surveys and ask our community members about what parts of code they share between different platforms.
2. Time savings
Due to code reusability, cross-platform applications require less code, and when it comes to coding, less code is more. Time is saved because you do not have to write as much code. Additionally, with fewer lines of code, there's less room for bugs to emerge, resulting in less time spent testing and maintaining your code.
3. Effective resource management
Building separate applications is expensive. Having a single codebase helps you effectively manage your resources. Both your Android and your iOS development teams can learn how to write and use shared code.
4. Attractive opportunities for developers
Many mobile engineers view modern cross-platform technologies as desirable elements in a product's tech stack. Developers may get bored at work when having to perform repetitive and routine tasks, such as JSON parsing. However, new technologies and tasks can bring back their excitement, motivation, and joy for work. In this way, having a modern tech stack can actually make it easier for you to both staff your mobile development team and keep it engaged and enthusiastic for longer.
5. Opportunity to reach wider audiences
You don't have to choose between different platforms. Since your app is compatible with multiple operating systems, you can satisfy the needs of both Android and iOS audiences and maximize your reach.
6. Quicker time to market and customization
Since you don't need to build different apps for different platforms, you can develop and launch your product much faster. What's more, if your application needs to be customized or transformed, it will be easier for programmers to make small changes to specific parts of your codebase. This will also allow you to be more responsive to user feedback.
Challenges of a cross-platform development approach
All solutions come with their own limitations. Some in the tech community argue that cross-platform programming still struggles with glitches related to performance. Furthermore, project leads might have fears that their focus on optimizing the development process might negatively impact the app's user experience.
With improvements to the underlying technologies, however, cross-platform solutions are becoming increasingly stable, adaptable, and flexible.
Here are the results of two Kotlin Multiplatform user surveys regarding framework usage, conducted 6 months apart:
Another commonly voiced concern is that multiplatform development makes it impossible to seamlessly support the native features of platforms. With Kotlin Multiplatform, however, you can use Kotlin's expected and actual declarations to enable your multiplatform app to access platform-specific APIs. Expected and actual declarations allow you to define in common code that you "expect" to be able to call the same function across multiple platforms and provide the "actual" implementations, which can interact with any platform-specific libraries thanks to Kotlin's interoperability with Java and Objective-C/Swift.
As modern multiplatform frameworks continue to evolve, they increasingly allow mobile engineers to craft a native-like experience. If an application is well-written, the user will not be able to notice the difference. However, the quality of your product will heavily depend on the cross-platform app development tools you choose.
The most popular cross-platform solutions
The most popular cross-platform frameworks include Flutter, React Native, and Kotlin Multiplatform. Each of these frameworks has its own capabilities and strengths. Depending on the tool you use, your development process and the outcome may vary.
Flutter
Created by Google, Flutter is a cross-platform development framework that uses the Dart programming language. Flutter supports native features, such as location services, camera functionality, and hard drive access. If you need to create a specific app feature that's not supported in Flutter, you can write platform-specific code using the Platform Channel technology.
Apps built with Flutter need to share all of their UX and UI layers, which is why they may not always feel 100% native. One of the best things about this framework is its Hot Reload feature, which allows developers to make changes and view them instantly.
This framework may be the best option in the following situations:
You want to share UI components between your apps but you want your applications to look close to native.
The app is expected to put a heavy load on CPU/GPU and performance is likely to require optimization.
You need to develop an MVP (minimum viable product).
Among the most popular apps built with Flutter are Google Ads, Xianyu by Alibaba, eBay Motors, and Hamilton.
React Native
Facebook introduced React Native in 2015 as an open-source framework designed to help mobile engineers build hybrid native/cross-platform apps. It's based on ReactJS – a JavaScript library for building user interfaces. In other words, it uses JavaScript to build mobile apps for Android and iOS systems.
React Native provides access to several third-party UI libraries with ready-to-use components, helping mobile engineers save time during the development process. Like Flutter, it allows you to see all your changes immediately, thanks to the Fast Refresh feature.
You should consider using React Native for your app in the following cases:
Your application is relatively simple and is expected to be lightweight.
The development team is fluent in JavaScript or React.
Applications built with React Native include Facebook, Instagram, Skype, and Uber Eats.
Kotlin Multiplatform
Kotlin Multiplatform is an open-source technology built by JetBrains that allows developers to share code across platforms while retaining the benefits of native programming. Its key benefits include:
The ability to reuse code across Android, iOS, web, desktop, and server-side while keeping native code if needed.
Smooth integration with existing projects. You can utilize platform-specific APIs while making the most of both native and cross-platform development.
Full code-sharing flexibility and the ability to share both the logic and the UI, thanks to Compose Multiplatform, a modern declarative cross-platform UI framework built by JetBrains.
No need to introduce a new language to your codebase when you already use Kotlin for Android. You can reuse your Kotlin code and expertise, which makes migrating to Kotlin Multiplatform less risky compared to other technologies.
If your team needs help adopting a new multiplatform technology, we recommend reviewing our guide on How to introduce multiplatform development to your team.
McDonald's, Netflix, 9GAG, VMware, Cash App, Philips, and many other companies are already capitalizing on Kotlin Multiplatform's ability to be gradually integrated, as well as its low adoption risk. Some of them opt to enhance their app stability by sharing specific, crucial segments of their existing Kotlin code. Others aim to maximize code reuse without compromising app quality and share all application logic across mobile, desktop, web, and TV, while preserving native UIs on each platform. The benefits of this approach are apparent from the stories of the companies that have already adopted it.
Conclusion
As cross-platform development solutions continue to evolve, their limitations have begun to pale in comparison to the benefits they provide. A variety of technologies are available on the market, all suited to different sets of workflows and requirements. Each of the tools discussed in this article offers extensive support for teams thinking about giving cross-platform a try.
Ultimately, carefully considering your specific business needs, objectives, and tasks, and developing clear goals that you want to achieve with your app, will help you identify the best solution for you.