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Flutter vs React Native vs Kotlin: Which will drive app development in 2023?

December 9, 2022

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Technology is turning around the software development sector. The global mobile app revenue is projected to generate more than 935 billion U.S. dollars in revenue via paid downloads and in-app advertising. Thus, new tech stacks are taking the world by storm, enabling competition in every sphere.

Flutter, React Native, and Kotlin are three seamless cross-platform tools for mobile app development that have started a new thread of competition. Read on to learn about their main advantages, key differences, and the best use cases for each, and decide which one will drive 2023 forward. 

What is Flutter? 

Released in 2017, Flutter is an open-source Google-built user interface (UI) software development kit powered by the Dart language (a Google answer for JavaScript problems). By offering an extensive toolkit along with Flutter API, ready-made code, documentation, libraries, and widgets, Flutter allows developers to build attractive and fast native-like cross-platform applications with a single codebase. Let’s go with the perks and drawbacks of working with Flutter. 

Who uses Flutter

Flutter is present in tech stacks of companies such as:

  • BMW
  • eBay
  • Square
  • Groupon
  • CapitalOne

Pros of using Flutter

From easy-to-learn language Dart to Hot Reload, Flutter offers a list of advantages that make it stand out from the competition. Let’s discuss the main benefits in more detail.

1. Open source and free

Flutter is an open-source framework that allows you to do heavy customization. This means you’ll get free access to the original code and documentation you need. Flutter’s documentation is user-friendly and easy to navigate. 

2. Rising popularity

Flutter's accessibility and Dart’s wide adoption lead to growing trust in this framework among software engineers. Flutter even received 1st place from GitHub for its cross-platform development solutions. While it is still not as popular in the US as it is in other countries, Flutter is on the fast track to becoming the first choice for mobile app software development. 

3. Ease of learning and ease of use

The Flutter/Dart combo for coders is easy to use and quick to learn. Programmers who have ever coded with Swift, React Native, and C-like syntax languages, can become easily productive in Dart and Flutter within weeks. Flutter framework ensures a simple installation that takes no more than 30 minutes and allows you to create fully functional apps with significantly less code (quite similar to Kotlin). 

4. Hot reload functionality

Flutter allows developers to see the output in real time. This means software engineers can edit their code, make changes to the back-end or front-end, and watch the changes instantly while the application is running. Therefore, there is no need of reloading the whole application when you build UI, add features, fix bugs, etc. That’s one of the most important advantages of cross-platform development over native one. 

5. Faster time to market

Flutter is a high-performance and cost-effective app development platform. The common codebase it provides enables faster product release and helps reduce the time to market.

Cons of using Flutter 

Nothing is perfect, and Flutter is no exception. We’ve highlighted the key disadvantages you may face while working with this framework.

1. Not as widely adopted

Let me remind you, you’re dealing with a cross-platform framework that’s even younger than Kotlin. There is still a deficiency of specialists in this framework. While Flutter is a powerful framework, there aren’t as many educational resources for beginners since Dart is less popular than Kotlin, Java, or C#. There are roughly 500 courses on Udemy that teach Flutter, while there are twice as many that teach Kotlin. This can provoke some hiring slowdowns. 

2. Shortage of plugins

When it comes to the plugins, due to the short existence of Flutter, it still loses the competitive edge against more experienced players, such as React Native. There’s a chance that you won’t find any plugin when you’ll try to create a more advanced functionality. So, you’ll need to write it on your own. 

3. Large app size

A significant downside of using Flutter is that Flutter-built apps are big. And this is a real problem for developers who are always trying hard to build apps compromising on their size. It’s worth mentioning that ReactNative is in the same boat here, but I’ll talk more about this framework later.

Top platforms with numbers % and grids
Cross-platform mobile frameworks used by software developers worldwide 

What is React Native?

Launched in 2015 by Meta (formerly known as Facebook), React Native is an open-source cross-platform mobile development framework based on JavaScript

Besides mobile applications, you can use React Native to develop web and desktop apps. Being a cross-platform, cost-effective, and reliable framework, React Native is often used by large enterprises. It gives developers a set of necessary foundations to create cross-platform applications, including widgets, documentation, libraries, and other tools and ensures a native-like feel and excellent performance.

Let’s dive into to find out what are the benefits of using React Native: 

Who uses React Native?

React Native powers several globally renowned brands:

  • UberEats
  • Skype
  • Tesla
  • Discord
  • Coinbase
  • Instagram
  • Salesforce
  • Gyroscope

Pros of using React Native 

Third-party plugins and modular architecture are some of the features that make React Native a standout option. Here’s a more detailed description of the key benefits. 

1. Live-tracking 

You will enjoy working with this framework, especially for its so-called Hot Reload feature. This feature allows programmers to see real-time changes in the application right after writing the code, enabling an automatic refresh of the application and its interface. 

2. Third-party plugins

Unlike most languages and frameworks (including Flutter) that don’t grant the use of plugins, React Native allows software engineers to use third-party plugins for a higher grade of flexibility, functionality, and customization. It is as well pointed out as React Native’s most superior feature by developers. 

3. Modular architecture

React Native’s modular programming enables developers to separate different functionalities into blocks or modules. Every block contains all the data needed to execute a certain function of the app. On top of that, the framework permits flexible and optimized coding flow as part of its declarative coding feature.

4. Higher performance

Another undeniable benefit of React Native is its high performance and cross-platform feature. You can have one team that will build products for Android and iOS with just one codebase. Infrastructure and feature development are performed simultaneously. Plus, the framework highlights errors on the move, provides pre-built components, decreases debugging time, and allows 90% reusability of the code, all contributing to increased performance and shorter development time. 

5. More experienced developers 

Developers skilled in React, whose number is in constant growth on the market, are capable of learning React Native quickly and efficiently. They can also write code in native frameworks and then add them to the codebase written in some sort of hybrid React Native. To sum up, it could be a great path in a developer’s career and a competitive option for a product owner.

Cons of using React Native 

React Native comes with some limitations. 

1. No match for native solutions

React Native is trying hard to close the gap between native programming languages. But the difference in performance is still evident. It’s mainly because of the JavaScript and UI code parts that are executed in two different threads. Software engineers provide the communication between them through a shadow thread, called React Native bridge. But it still affects the workflow. Even if the code works faultlessly in separate threads, the issues in the React Native bridge affect the application's performance.   

2. Difficulties in debugging

According to devs, that’s a frequent problem with React Native. The debugging issues are one of the reasons for building the application on separate threads. As a solution, developers can integrate the framework with Flipper - a special platform that provides a set of tools like bug reports, log preview, local database, and performance inspector. This way, they can overcome debugging problems. 

3. Not the best choice for highly advanced applications

If you’re planning to build mobile apps with complex effects, React Native is not the case. Only native programming guarantees to implement screen transitions, animations, and interactions smoothly. 

What is Kotlin?

Unlike Flutter & React Native frameworks, Kotlin is a cross-platform programming language. Launched by JetBrains, Kotlin is an open-source, statically typed, and general-purpose single language designed to interoperate with Java. Being an indispensable part of Android app development, it’s used by 60% of professional Android developers. It’s also estimated that 80% of the top 1,000 Android apps used Kotlin code, including over 60 Google apps. Moreover, PYPL ranked Kotlin as the 12th most popular programming language in the world. Besides Android, its multi-platform capabilities allow programmers to share code, logic, and data across several platforms such as iOS, Web, and more. 

Programming languages of the top 1,000 Android apps 

Let’s move to the features that make Kotlin so powerful. 

Who uses Kotlin? 

Kotlin has been utilized by many big players like: 

  • Slack
  • Evernote
  • Tinder
  • Trello
  • Netflix
  • Airbnb
  • Pinterest

Pros of using Kotlin

In this part, we will sort out the benefits of using Kotlin and compare it with Flutter.

1. Interoperability with Java

This means it’s straightforward to convert any pre-existing Java code and you have full access to Java libraries. Even though you have thousands of code lines in Kotlin, you can easily convert them one after another with no harmful effect on your codebase and software development process. This compatibility makes both writing and application migration from Java to Kotlin much faster. This Kotlin advantage is especially valuable, which makes it go one step ahead of Flutter and React Native, where you need to jump from one technology to another. 

2. Clear and concise code

Kotlin’s straightforward syntax enables clearer and more compact code. As a result, software engineers get significantly fewer lines of code in comparison to other programming languages and frameworks. Less time writing allows more reliability, simplicity, and acceleration of the software development process, making software teams more efficient and result-oriented. 

3. Safe and reliable 

This benefit is bound to the reduced frequency of errors while writing the code. Due to a shorter and easy-to-read codebase and its special functionality called Require, Check, Assert, Kotlin gives programmers triple confidence that bugs are spotted and fixed early on. The Kotlin creators focused on making it look like an upgraded version of Java (a goal they definitely achieved), which makes it a standout option in the Flutter vs React Native vs Kotlin performance race. 

4. Supportive community

Kotlin community is made of large, well-qualified developers that are fully committed to making regular improvements to the product. You can always listen to podcasts, discuss the hot Kotlin subjects on forums and follow their Twitter accounts for more updates - experienced Kotliners are always happy to share their knowledge with you on any issues that might arise during the software development.

5. Kotlin Multiplatform 

With the introduction of its experimental feature called Kotlin Multiplatform, Kotlin is seen as a cross-platform application development tool. It allows developers to nail the app building on both Android and iOS. 

Cons of using Kotlin

So, Kotlin shines bright, but let’s reveal some darker sides of this language. 

1. Limited workforce

Kotlin can still be considered a rather new player on the market, even though it was released ten years ago. Because the programming language is relatively new, the challenge to find skilled Kotlin programmers is considerably higher than with older languages. However, with years Kotlin gained more traction and we’re expecting this tech stack to boom the IT world. 

2. High maintenance cost

Kotlin SDK features aren’t fully native, which means the cost of building mobile applications skyrockets. Kotlin is an expensive programming language, especially when building prototypes and minimum viable products (MVPs). 

3. Long compilation time

One more drawback of Kotlin is its slower compilation speed. Yes, Kotlin may do a decent job when compiling incremental changes, but it’s still not as quick as the other modern options like Flutter. 

Brief comparison: popularity, documentation, and many more 

Popularity 

In terms of popularity, React Native, Flutter, and Kotlin are highly popular among mobile app developers. React Native is the third most widely used framework among the top US apps, directly after Kotlin. React Native is still popular in the US because over 14.84% of the top 500 apps are built using this framework. 

Kotlin is used by TikTok, Instagram, and Microsoft OneDrive, in addition to Google, and enjoys an impressive 15.99% market share. It has been used in the development of more than 131,000 various apps and boasts more than 298 billion downloads worldwide.

Flutter’s popularity skyrocketed in the last two years and is expected to surpass React Native. The annual study by Stack Overflow ranked Flutter fifth on the list of most popular frameworks and libraries. 

orage, navi and blue lines, diferent sizes
Flutter versus React Native from 2019, 2020 and 2021

Developer availability

Compared with Flutter, the demand for Kotlin and React Native is as high as the supply. The talent crunch is one main reason why a limited number of companies choose to work with Flutter.  

Documentation

Even though React Native and Kotlin have been around for much longer than Flutter, Flutter’s documentation is well-developed, in-depth, and easier to navigate. 

When you need developers to jump into a project fast, Flutter’s documentation will help. For example, Flutter provides “get started” sections for devs with diverse tech backgrounds and levels of experience. So both React Native and Kotlin developers looking to start working with Flutter can easily find what they need. 

Maturity

We can say that all these technologies have matured enough to be safely used in mobile app development. React Native and Kotlin have a lot of high-quality third-party libraries and have been incorporated into the tech stacks of big tech giants. Flutter is catching up fast, though.

Learning curve 

From a developer’s point of view, Flutter is easier to learn than React Native. Dart as a programming language is easier to work with than JavaScript which is far from being named the friendliest programming language. Compared to Kotlin, Flutter has comprehensive documentation and resources available which makes it easier for developers to learn and kickstart with app development. Because of that Flutter has been placed 2nd in the “Most Loved Technology - Frameworks and Libraries” category in the Stack Overflow Survey 2021. 

Community

Flutter, React Native, and Koltin have flourishing communities around them, with plenty of conferences, hackathons, and events happening annually.

What is better in 2023?

When choosing either tech stack, you should look at it from a wider perspective than just popularity, documentation, or learning curve. 

React Native and Flutter are great for fast prototyping and simple mobile apps. However, when building enterprise mobile applications where designs, performance, and instant implementation are key requirements, then native development might be a better choice. 

So, what’s the final verdict? Who will win this fierce cross-platform battle in 2023?

The final verdict: Flutter

The leadership position of Flutter in the rankings of the most popular cross-platform frameworks is no longer a surprise. And it’s hard to be considered a one-season wonder.

Business impact for start-ups and SMEs is higher with Flutter. The framework offers faster app development, easy integration, high performance, and flexible UI. It can be used in small, medium, and large companies and is best shown in developing online stores, fintech, and business applications. 

Flutter is a top choice for creating MVPs and working prototypes, due to its unique UI and hot reload features. Considering its impressive surge in popularity in just a few years and Google’s continuous support, Flutter's future is bright.

Flutter works well when: 

  • You have a smaller budget 
  • You need to release your product fast
  • You want to have pixel-perfect designs and great UI
  • You need to build a cross-platform experience for your users

So, weighing all pros and cons, I can risk the statement that 2023 is set to become a year of Flutter.

The final verdict: React Native 

React Native is great for fast prototyping and simple mobile apps. The ranking is still strong for React Native, even though its popularity slightly dropped from 42% to 38% recently. And, if no breakthrough happens, the further drop may continue. The biggest challenge for React Native now is closing the gap between Flutter and the native language in the upcoming 2023. 

React Native is great for fast prototyping and simple mobile apps. 

React Native works well when: 

  • You have a desktop app or website and can reuse components for mobile application development
  • You pressed for time to find a team of developers, since Flutter developers are currently in demand and harder to find
  • You have a team of JavaScript familiar with your current assets and can use the plug-ins, modules, and widgets from the huge npm repository

The final verdict: Kotlin

The significance of Kotlin will only grow in 2023. One of the main reasons for this growth is full interchangeability with Java. Kotlin aims to eliminate the “narrow places” in Java, which makes life much easier for programmers. 

The level of Kotlin benefits overshadows its weaker points. However, it can still be seen as an option for senior players in the application development market. The high maintenance costs and talent crunch make it a risky investment for start-ups. 

Kotlin, after all, is better when:

  • You start a new project for the Android 
  • You need to make quick adjustments to the existing project 
  • You do any kind of development, be it server-side or client-side web, and Android

To hire and get hired as Flutter, React Native, and Kotlin developers, is a time-consuming and challenging adventure, as skilled software developers are in high demand today. You must define your project requirements, hiring budget or rates, and time you are willing to spend on recruitment. If you wish to build a strong software development team and release your product faster, let’s talk. Index is a global talent network that matches senior, pre-vetted remote Flutter, React Native, or Kotlin developers with tech companies at unbeatable prices. 

If you are a senior Flutter, React Native, or Kotlin engineer looking for a remote job, Index can help. With Index, you can work for the top US, UK, and EU for full-time and long-term engagement, at your own pace and rate.  

For other good reads on Python frameworks, Kubernetes, and best hiring practices, visit our blog