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Flutter vs. Swift for iOS Apps: Which one is better in 2021?

April 2021

There’s an app for everything, and if your business doesn’t have one, you may be missing out on potential revenue. Customer demand for reliable, user-friendly apps has never been higher. Fortunately, advances in mobile technology have made it easy to develop high-performing iOS and Android applications.

However, before you begin building your app, you’ll have to determine which framework will work best. The two main choices for iOS app development are Flutter/Dart and Native iOS/Swift. So, we’ve provided this mobile app framework comparison to help you figure out which framework or language is right for your project.

An Overview of Flutter vs. Swift in 2021

In 2014, Apple released its multi-paradigm, compiled programming language, Swift. It is an open-source, general-purpose language designed for native iOS development. Swift offers many benefits, including:

  • Excellent documentation
  • Free and open-source
  • Good code readability 
  • High speeds
  • Advanced functionality
  • Dynamic libraries for easy scaling

Flutter, on the other hand, is an open-source, multi-platform mobile SDK developed by Google. It uses the Dart programming language, and Flutter allows you to build iOS, Android, Linux, Windows, Mac, Google Fuchsia, and web apps all from the same source code. Flutter offers the same benefits as Swift, with several added perks. Flutter advantages include:

  • Free and open-source, with a greater number of users
  • Great documentation
  • High speeds
  • Graphics engine
  • Variety of useful tools to speed up development
  • Hot reload
  • Support for older devices
  • Widgets for easy interface creation

Flutter vs. Swift Speed

App build times are pretty much always faster when you use native programming languages. So, when you look at clean build times for Flutter vs. Kotlin or Swift, the latter languages are almost guaranteed to be faster. However, when you look beyond the initial clean build, additional Dart builds increase in speed and the language becomes more competitive.


When considering time-to-market for Flutter vs. native iOS development, Flutter really shines. Very few companies want just one single-platform app, so if you use Swift to build an iOS app, you’ll also have to develop a separate application for Android. This can get quite expensive, since the developers will have to build two separate codebases.

However, when you use Flutter for cross-platform app development, you can utilize one code base to develop apps for multiple platforms. Not only will the apps all work perfectly on their respective operating systems and devices, but you will also reduce both development and maintenance time and expenses.

In addition, development is simply faster with Flutter. There are several Integrated Development Environments (IDEs) you can use to speed up Flutter app development, including Visual Studio Code, which has many of the same features as Android Studio and IntelliJ, but it is much lighter and faster. You can get a basic Flutter MVP on the market within a couple of months and add new features over time. Rather than waiting six months or more to launch a fully-developed application.

Plugins and code reusability

We’ve already mentioned Flutter’s fantastic code reusability and the advantages of using a single codebase to develop apps for multiple platforms. This capability also reduces testing times, since the developers won’t have to test app performance for two completely separate applications, as they would if you used Swift and other native frameworks. Flutter also offers a wide variety of plugins for faster and easier development.


If you have a big budget to develop distinctly separate apps for each platform, then Swift is a great way to go. You’ll get smooth, fast, reliable apps using native frameworks for development. However, a smaller budget doesn’t mean that you have to compromise on performance.

Flutter apps can provide native-level performance across all platforms, since they run using natively compiled code, without interpreter interference. In addition, the Flutter animation package makes it easy to build a sleek, intuitive UI. Most of the Flutter animation widgets feature pre-set effects, however, they are also customizable to your specific needs.

Popularity and Use Cases

In a 2020 Stackoverflow survey, Flutter was ranked in the top three most preferred frameworks, libraries, and tools. Flutter has 118K stars on Github, as opposed to Swift’s 55K. However, both frameworks have been used to create an impressive variety of applications.

Swift Apps:

  • LinkedIn
  • SlideShare
  • Lyft
  • Firefox
  • Eventbrite

Apps built with Flutter Framework:

  • Google Ads
  • Alibaba
  • Square
  • Ebay
  • Hamilton Musical
  • Reflectly
  • Groupon
  • Cryptomaniac
  • SpaceX Go

As you can see from the Flutter app examples, the framework can be used to build a massive variety of applications for businesses of all sizes, including retailers, financial organizations, suppliers, franchisees, and eHealth companies.

However, when considering Swift vs. Dart, keep in mind that there are some Flutter limitations and situations where you might be better served by a native framework. For example, you may not want to use Flutter if:

  • Your app size will be very small (1-3 MB), since Flutter apps tend to be larger than native apps.
  • You need to use hot code pushes to skip the App Store review process when updating your app.
  • You’re developing a more complex game, like PUBG. Flutter is designed for apps, not games, however, the framework does work great for simple games.

Additional Flutter Features for iOS Apps

When looking to choose the right framework for iOS app development, don’t think that all of the cool Apple solutions are only compatible with a native framework. You can seamlessly integrate the following features into your Flutter iOS app.

  • Apple HealthKit - allows your app to read and write the user’s health and fitness data to their Health app, adding another level of information and pairing flawlessly with their current solution.
  • Machine learning - leverage on-device machine learning to develop innovative, powerful features, giving your users a brand new experience.
  • HomeKit support - gives your users the ability to seamlessly connect your app and devices to their current smart home system and control them using Siri.

Flutter Audio

When we were building Medcorder application for our client, we ran into a problem: there wasn’t a way to record speech using the Google-provided APIs. The client who we were developing the project for came up with the idea of the development of the audio recording plugin as an open source contribution. So, we built an audio recording plug-in for the project! Here is a nice article on it.


Swift is a great native framework, in its own right, but Flutter offers numerous benefits, including the ability to develop apps for multiple platforms using a single source code. Flutter works flawlessly for a huge variety of applications, it enjoys more community support, and it will save you time and money on development. Swift works very well for native apps, however, as Flutter continues to improve, it may even surpass Swift for iOS app development.

If you want to develop an iOS mobile app using Flutter, contact us to learn more about what the framework can do for you.

I love seeing new plugins like Flutter Audio by Evrone: tightly focused on doing one thing well. Lots of interesting ways to use this for mobile apps. Thanks Evrone for making Flutter better!
Tim Sneath
Director of Product and UX for Flutter & Dart, Google
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