Flutter vs Swift: Which One To Choose For iOS App Development?

Even though Google’s Android platform ultimately has more downloadable apps, Apple controls a significant portion of the mobile app market. There are currently over 1.6 million iOS apps in the market. For any business looking to join this ever-growing iOS trend, deciding on which platform you’ll use to build your iOS app is the first step. 

Flutter and Swift are two of the most recommended technologies for building iOS apps. While Swift is exclusively for building native iOS applications, Flutter is a cross-platform mobile app development tool, which means it can be used to create apps for both Android and iOS devices. In this post, we will look at the features and benefits of each of these development technologies to determine which of them you should choose for your iOS app development needs. 

• Swift is a programming language for building apps for Apple’s ecosystem, while Flutter is a UI development framework for building smooth and efficient cross-platform frontends.
• Since Swift is a native coding language that follows the recommended syntax for iOS apps and can leverage native hardware features, it tends to deliver better-performing iOS apps.
• Flutter’s pre-built widgets will help you build native-like UI/UX elements quickly and efficiently.
• If the goal is to build for multiple platforms now or in the future, Flutter might be the faster and more cost-efficient choice. 

Flutter Overview

Flutter is an open-source framework developed to create applications that work across multiple platforms using a single codebase. Created by Google in 2017, this framework comprises a Software Development Kit (SDK), which is a set of tools needed to develop a functional mobile application that works for Android and iOS platforms as well as web applications. 

The Flutter framework includes reusable widgets and UI components for building natively compiled user interfaces quickly and efficiently. Flutter is built on Dart, a programming language developed by Google. This general-purpose programming language offers modern features that help to create high-performing apps that behave consistently across multiple platforms. Dart’s syntax and architecture also simplify and speed up the development process. In fact, Flutter’s ability to build interfaces effortlessly has made it popular among developers. 

For more about how multi-platform development with Flutter compares to native development, you can read our Flutter vs Native, Flutter vs Dart, and Flutter vs Kotlin articles. Our blog also has articles comparing Flutter to other cross-platform app development frameworks like React Native as well. You can read more about it in this Flutter vs React Native post.

Top Flutter Features

Multi-platform Development

Flutter is a cross-platform mobile app development framework. This means developers only need to write a single code base for both Android and iOS apps when they use Flutter. This framework’s cross-platform capabilities can help businesses save a lot of time and effort on development while still getting an application with native performance and feel. 

Hot Reload

The hot reload feature is one of the best things about the Flutter framework. With this feature, changes made to the app code can be viewed simultaneously in the application. This speeds up the process of debugging and deploying changes to the production-stage application, making the development process more efficient.

Widget Library

Flutter has a widget-based architecture, which means the user interface of Flutter apps is constructed using pre-built widgets. These reusable building blocks can be incorporated seamlessly into app designs. The widget library is quite extensive with lots of customizable elements for building visually appealing user interfaces with native-like capabilities. The use of widgets for building mobile apps in Flutter also promotes a consistent approach to UI development.  

Native-like Performance

Although Flutter is a cross-platform framework, Flutter apps still deliver native-like performance. This is because Flutter uses platform-specific widgets and API to execute specific features, resulting in better performance. For instance, Flutter’s animation package allows developers to build sleek and intuitive user interfaces.

The framework’s architecture further reduces the overhead of integrating these APIs. Consequently, Flutter apps are characterized by fast startup times, smooth animations, and transitions. Flutter also leverages Dart code’s garbage collection feature to optimize performance. The code is compiled to machine code ahead of time (AoT), allowing quick and efficient communication with the device. 

Open-source

As an open-source platform, Flutter’s source code has been made available to a large and active community of developers who are working consistently to improve it. In addition to making changes to the framework, Flutter developers are also actively building widgets and UI components for the framework, leading to a vast ecosystem of third-party packages and libraries to extend its capabilities. Being open source also helps to reduce development costs and the community-driven resources accelerate Flutter development.

Best Flutter Examples

• Google Ads 
• eBay 
• Google Pay 
• Alibaba 
• BMW

Swift Overview

Swift is not a mobile app development framework like Flutter. Instead, it is a modern programming language developed by Apple mainly for the development of native apps for the Apple ecosystem. Swift can be used to build iOS, macOS, watchOS, and tvOS applications. 

Swift is an open-source programming language renowned for being robust, straightforward, and easy to use. Apple created this programming language in 2014 to replace Objective-C, which used to be the primary programming language for Apple Platforms.

The goal was to create a programming language to improve developer productivity and streamline development. Swift also comes with several built-in safety features designed to prevent some of the common programming errors and bugs that can lead to app crashes. 

As an iOS development language, Swift offers direct access to native iOS components. This direct access to hardware components translates to several potential performance benefits. 

Since Swift is not a development framework, comparing it to Flutter isn’t exactly accurate. However, the Swift programming language uses a wide range of UI frameworks similar to Flutter including SwiftUI, Realm, Core ML, Kingfisher, and Firebase. Swift is a native coding language, which means it is exclusively used for building native iOS apps and not for multiplatform development like Flutter. 

A more accurate comparison will be to compare Swift vs Dart, which is Flutter’s programming language. We have a detailed article that compares both languages on our blog. Swift is also comparable to Kotlin, which is its native equivalence for Android app development.

You can read our Swift vs Kotlin article to see how these two tools compare against each other. You should also check out our React Native vs Swift blog post to see how Swift compares to other cross-platform frameworks apart from Flutter. 

Top Swift Features

Easy-to-use Syntax

The Swift syntax is generally easy to read and write. Unlike other languages such as Objective-C which it replaced, Swift introduced a cleaner and more modern syntax that was considerably easier for developers to learn and use. The simplicity of this programming language also eases development and speeds up coding.  

Swift’s code is also considered more expressive and concise. The language uses more functional programming concepts like closures, higher-order functions, and map/filter/reduce operations. This programming paradigm makes it easier to maintain and reuse Swift code. 

High-end Security

Another highlight of the Swift programming language is how it prioritizes safety. In fact, Swift was introduced to resolve some of the common safety issues with other languages such as null safety, which could lead to runtime errors. With Swift, variables are always initialized before they’re allocated. This ensures that they cannot be used after they have been deallocated. 

In addition to eliminating null-safety issues, Swift’s status as a strongly typed programming language also helped to simplify error handling in production. The programming language has a short feedback loop, so errors can be identified quickly and fixed. This reduces the chances of deploying apps with low-quality codes. 

Better Memory Management with ARC

One of the problems with earlier languages used for iOS development was their excess memory usage. This was a problem with older versions of Swift as well. However, as the programming language evolved, a new method of automatically setting the memory space within an application was created. 

The latest versions of Swift now use a method known as automatic reference counting (ARC) for memory management. ARC can determine which class instances are no longer in use and eliminate them automatically, reducing the memory footprint of your app. This leads to increased performance of Swift apps with no memory lagging. 

Interoperability

Although Swift was introduced to replace Objective-C, it is still fully interoperable with the older programming language. This makes it easier for developers to gradually transition existing Objective-C codebases into more modern Swift code or leverage Objective-C libraries and frameworks for their development. 

Developers can either add new features to their existing codebase using Swift or use Swift libraries and other elements for their existing projects. This is a lot better than having to rewrite an entire codebase already written in one programming language. 

Reusability and Speedy Development

Swift promotes reusability through generics. These are functions and types that are flexible and reusable across multiple projects. This reuse of functions makes handling applications in Swift quite flexible. Swift codes are also reusable across multiple Apple platforms including iOS, macOS, and WatchOS. Many of Swift’s frameworks and APIs also support the creation of components that can be reused across various iOS applications, making the development process a lot more efficient. 

Best Swift Examples

• LinkedIn 
• Airbnb 
• Whatsapp 
• Todoist 
• Slack 
• Notion 

Detailed Comparison of Flutter and Swift

Cross-platform Development 

This is the primary difference between Swift vs Flutter. Flutter is the number one framework used by developers to create cross-platform applications. This mobile app development framework allows developers to build apps that work on both Android and iOS devices without writing separate codes for each platform. To develop apps for multiple platforms, Flutter relies on the Dart programming language, which is arguably the best platform-neutral programming language in terms of performance and ease of use. 

Swift on the other hand does not support cross-platform mobile development in the strict sense. While it can be used to build apps for iOS, WatchOS, MacOS, and tvOS, these are all Apple’s operating systems. Of course, being a native coding language means Swift’s codes are highly optimized for Apple devices, leveraging the full potential of the platform. 

User Interfaces 

Flutter is a development framework for building robust user interfaces for mobile applications. It offers a rich set of widgets and tools that allow developers to build or customize responsive UIs. The fact that these user interface elements are prebuilt and are flexible for easy customizable also speeds up the rate of building these complex UIs. Interfaces built with Flutter replicate native performance as closely as possible. 

However, Swift being a native iOS language means users can implement full native iOS interface features with no issues. Apps created with Swift can leverage the capabilities of iOS devices to deliver a fully native user experience. As far as building these interfaces goes, Swift offers a rich set of APIs and works with a wide range of UI frameworks. 

Performance 

An app’s performance is closely tied to the quality of your code and the efficiency of the frameworks used in creating it. Generally, since Swift is a native programming language, the code is more optimized to boost app performance on the iOS platform.

This allows you to build smooth and reliable applications that can fully leverage the platform’s full strength. It’s the ideal tool for creating apps that require significant power. In addition to its native capabilities, Swift’s use of the Automatic Reference Counter (ARC) for memory management further ensures that Swift apps utilize memory effectively.

Flutter is also efficient at building high-performing cross-platform applications. The framework’s layered architecture is designed to minimize the resource overhead for platform-specific API calls. This results in apps with great performance.

Flutter also leverages Dart’s garbage collector to compile code ahead of time, allowing quick communication between the code and the device. Consequently, Flutter can still be used to build sleek and highly intuitive apps with animations, transitions, and other advanced effects. 

Development Cost and Time 

Since Flutter allows you to develop apps for Android and iOS platforms simultaneously, it is ultimately cheaper and faster to build with it compared to Swift. In addition to allowing you to build for multiple platforms from the same codebase, Flutter also offers a lot of additional features to boost the development speed. The framework has an abundance of custom widgets, component libraries, and testing tools that make development faster. 

Developers building Flutter apps also don’t have to worry about polishing UI elements since this is handled automatically by the framework. You’ll write less code to build a Flutter app than you would do building the same application with Swift. 

Another attribute of Flutter that speeds up development is the hot reload feature. It ensures that all changes made to the code are reflected in the app instantly with no need to reload manually. 

While Swift only allows you to build apps for iOS alone, it is still a quick and efficient way to build apps. Swift allows developers to build fast. The expressive nature of this programming language also makes it easy to debug and maintain in the long run. However, it may take longer for changes made to the code to reflect in the app. 

Learning Curve 

Flutter is quite easy to learn. Professional developers who are already familiar with object-oriented programming languages such as Java or Kotlin will find it easy to master Flutter’s programming language (Dart). The framework also has extensive documentation with detailed explanations and robust community support to make it easy to learn. 

Although Swift also offers detailed documentation and great community support, it is generally more complex to learn compared to Flutter, especially for developers who are not already familiar with functional programming or iOS development. The development environment is generally more complex to master compared to Flutter. 

Application Size 

Flutter apps come with an included framework and engine, which can increase app size. This isn’t the case with Swift since it is a native programming language and can use platform APIs directly. 

Swift has a compiler that can optimize app performance while also reducing the overall size of the application. It also comes with a wide range of options to optimize the whole module and link time all of which contribute to a further reduction in app size. As a result, the average app size for Swift is typically about 25MB while the same app built with Flutter will be about 52.4MB in size. 

When to Use Flutter For iOS App Development?

• Cross-platform app development with a single codebase
• When you prioritize consistent user experience across multiple mobile platforms 
• When you intend to cut costs and reduce development time 
• Building MVPs: Flutter’s rapid development capabilities can be beneficial for quickly creating MVPs
• When your team is primarily familiar with object-oriented programming languages

When To Use Swift For iOS App Development?

• Developing iOS apps with native code
• For apps with high-security requirements 
• When you need to update an existing Objective-C code base
• Complex apps with large codebases, such as games and social media or messaging apps.  
• Performance critical apps 
• Software solutions that need to use Apple’s latest features 
• When your developers are familiar with Objective-C and other object-oriented languages

Conclusion

As this article shows, both Swift and Flutter have their own unique benefits for iOS app development. Generally, Swift presents more benefits when the goal is to build powerful and secure native apps that can leverage the full capabilities of the iOS platform. However, Flutter offers better development speed and faster time to market, especially if you still intend to build for other platforms aside from iOS. 

Regardless of your choice between these two options, our team at CrustLab can help you build a powerful and efficient app with either of these two programming languages. If you’re unsure of which one to choose, our dedicated and highly experienced software development team can help you find the right fit for your project’s unique needs. Contact us today to discuss your project and find the right coding language or framework for you.