What is Flutter?

Flutter is a cross-platform framework that enables building applications for mobile devices (iOS and Android), desktop (Mac and PC), and web browsers from the same codebase.

It allows for shortening the app development process and giving significant savings in the Total Cost of Ownership for the Product Owners. Flutter has been used for over 700K iOS and Android apps with more than 150M+ users.

Flutter is also an open-sourced mobile UI framework written using C, C++, a programming language called Dart, and Skia Graphics Engine, developed by Google and released in beta in May 2017 (the first stable version was released in December 2018). 

Flutter is used to build cross-platform apps, which means iOS and Android applications built with Flutter use a single codebase, compile directly to the ARM native code, and access the platform APIs and services without any communication bridge.

With Flutter, you can create well-performing, user-friendly, and beautiful apps in no time. We believe Flutter offers even better solutions than React Native (which also can be used for mobile app development).

If you are ready to build your next app, see LeanCode mobile app development service.

The current state of Flutter technology

Flutter framework has its core components being developed by the Google Team, which is a plus for its further development and stability. Even tho, Flutter is still new technology it's a fully stable solution. Google team takes care of its stable support and is transparent about the development roadmap, planning at least one year ahead and considering developers' opinions while making fixes and improvements. 

Moreover, Flutter supports building apps on a wide variety of devices and form factors, including web, mobile (iOS and Android), and desktop (Windows, macOS, Linux); living rooms (TV, Stadia); smart displays (Assistant); and beyond (cars, embedded devices, and appliances).

Flutter helps its users to create the best experiences for their applications with its fast, productive, open, and pervasive toolkit. It also allows for the implementation of solutions necessary for accessibility support. It is also constantly developing - the Google Flutter team announces changes regarding the development of Flutter on average 3-4 times a year.

The major change in Flutter 2.0 version was to confirm the sound null safety, which is mathematical proof that no object references will have null or void values. Flutter 2.10 covered a wide range of improvements, including updates across Android and iOS, and the web. Another significant change was allowing the production of Windows apps on the stable channel of Flutter by default.

Flutter 3.3 version came along with Dart 2.18.1 and brought some exciting widgets, features, DevTools, and useful VSCode extensions that can improve app development. Google is also working on increasing its supply chain security and bringing the infrastructure in line with the requirements described in SLSA documentation. They have achieved Supply Chain Levels for Software Artifacts (SLSA) Level 2 security.

Besides that, the broad developer community is an additional source of market credibility for the product. Since Flutter's early days, it has been attracting developers who emphasize the ease and speed of Flutter app development (thanks to Flutter's architecture), even with a demanding user interface (visual components) and complex animations. Plus, it's a multi-platform solution (for iOS and Android apps).

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What are the advantages of using Flutter?

The number of applications built in Flutter is growing. Even such prominent brands as Toyota, BMW, iRobot, eBay, and Groupon decided to take advantage of this framework. Nowadays, it also becomes a popular solution for such complex projects as mobile banking apps.

Let’s take a look at the main advantages of using Flutter:

Declarative UI:

Flutter does its own UI drawing, which frees us from being dependent on the operating system version. Also, the declarative style of Flutter’s UI programming means you describe only once what the UI should look like for any given state.

Effective Dart language:

Dart is the main programming language in Flutter. It is also a client-optimized language for developing fast apps on any platform, mainly because the same Dart scripts without modification work in iOS and Android native apps without modification.

Many open-source libraries:

Flutter is an open-source project with contributions from many companies and individuals worldwide and from Google. The availability of many open-source libraries speeds up the Flutter app development time.

Great documentation and community:

Flutter has an engaged community that impacts the improvements and the ease of use. So when developers come across issues with code, they can look at Flutter's well-written documentation with many detailed and interactive examples of basic use cases.

Single codebase:

Flutter is a set of software development tools and a cross-platform solution, which allows it to build web, mobile, and desktop applications from a single codebase. It significantly increases the speed of development.

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LeanCode is an expert in Flutter

At LeanCode, we gather 25+ skilled Flutter Developers that help our clients to build well-performing applications with UI and UX experience on the highest level (similar to native performance). 

We can ensure that Flutter framework provides an excellent opportunity to deliver mobile apps much faster than the other cross-platform solutions. Why do we call ourselves experts in Flutter?

1. Flutter is our core mobile technology

We think the Flutter framework is a great solution for mobile applications, and that’s why we fully focus on this technology. We have been developing mobile apps in Flutter since 2018, and we deliver several mobile projects for our clients every year. It allowed us to develop the skills of our Flutter team to a very great extent, and you can take advantage of it while working with us. If you have chosen Flutter already, you can be sure that LeanCode is a top Flutter company.

2. A large Flutter team means more possibilities

We gather 25+ Flutter Developers, and our team is still growing. It gives many possibilities - from developing smaller Flutter applications to those dedicated to enterprises in the creation of which a dozen or so Flutter Developers are involved. Besides that, our Flutter team members have already moved from general skills to specialization in specific solutions such as Bluetooth technology, payments integrations (Stripe, Google Pay, Apple Pay) design systems, media services, etc.

3. We have a CoreLibrary for Flutter

We have a LeanCode CoreLibrary for building mobile apps in Flutter. This library contains Flutter packages created by us, such as user authentication, Flutter communication with the backend services, or chat. We also have experience developing and maintaining component libraries within a design system.

All of that plus our Flutter and Dart packages simplifies and speeds up the work of our team by reducing the need to write additional code and reducing the number of bugs that could arise. The fact that specific solutions have already been tested and are compliant with security standards (of Android apps, iOS apps) increases the application's stability.

4. We are involved in the development of the Flutter Community

We are a part of the Flutter Community. LeanCode engages in organizing the Flutter Warsaw Event (the biggest European Meetup dedicated to Flutter with 1.8K+ members). There were 17+ editions already. We also organized the Flutter Europe Conference. Our Flutter Developers built many Flutter cross-platform applications and they share their knowledge by supporting open-source projects and giving speeches at tech conferences both in Poland and abroad.

5. We teach good Flutter practices at the university

We are in constant cooperation with the Warsaw University of Technology, where we teach Flutter theory and practice. We also take part in other educational events dedicated to future developers. Every year we also run LeanCode Internship, where students and graduates have the opportunity to work on an actual mobile application project and learn Flutter best practices by working in a real project team during a two-month program.

6. We have been developing the Flutter UI testing framework

LeanCode is developing Patrol – a Flutter-first UI testing framework that revolutionizes the way we test our Flutter apps. We use Patrol internally, but it's also an open-source project. We shared it with the Flutter community to create even better Flutter apps. Patrol can drive your Flutter app in a way that no other tool ever could. It can interact with the operating system UI, open the notification shade, and toggle Wi-Fi and Location so that you can test truly real-world scenarios.


We build communities

A photo from Flutter Warsaw event
Flutter Warsaw is an IT community focused on modern Flutter technology. It is one of the largest so-called meetups dedicated to Flutter in Europe, initiated by LeanCode in 2018 in Warsaw, Poland with over 1.8k members worldwide. It gathers Flutter enthusiasts and other IT professionals interested in getting to know its possibilities.
A photo from Flutter Europe conference
Flutter Europe is an initiative driven by European Flutter Communities to gather people passionate about Flutter and those who want to learn how to create beautiful applications. Its last edition, one of the biggest Flutter conferences, took place in 2020 in Warsaw, Poland. It was organized to share Flutter's knowledge further.

How else can our clients benefit from using Flutter?

High Flutter app performance:

Flutter aims to provide 60 frames per second (fps) performance or 120 fps performance on devices capable of 120Hz updates. Even though it is a cross-platform framework, it matches the performance of native apps.


The cost of building an app often depends on the number of operating systems where it should be available. When you take this into account, developing applications in Flutter is cost-effective since developers use the same code twice.

Less testing:

Again, the fewer versions of code are required, the less testing is needed. A development team doesn’t need to write several tests for each platform which accelerates and simplifies the release process.

Hot reload:

Hot reload allows a developer to edit code and apply those changes immediately. Flutter has a hot reload feature, so when a change to the code appears, it can be seen instantly in the application, which positively impacts development.

Easy integration:

Flutter can be integrated into existing applications piecemeal as a library or module. It means you don’t always need to rewrite all of your existing app’s code to Flutter. This feature is called add-to-app.

You can read more about Flutter app development pros and cons in our article.


Take advantage of our Flutter team!



Antoine Azaïs
We are highly satisfied with the cooperation with LeanCode as a trustful tech partner.
Marta Kutyna Bakalarska
Head of Innovation at Maspex Group
LeanCode has managed to create the great project on time and within the budget estimated. The team effectively managed the project using an agile methodology.

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Flutter is suitable not only for mobile development

Flutter framework was created with the intention of supporting the development of mobile applications primarily. However, with the development of web rendering technologies like HTML, CSS, JavaScript, and Flutter's capabilities (Flutter 3.0 release), it has also become suitable for web app development. It is also still developing to support different platforms.

Using Flutter, the existing code can be easily compiled into a client experience, embedded into the browser, and then deployed to any web server. Flutter offers support for Desktop devices, meaning mobile applications can be scaled to Windows, Linux, and macOS without needing to rewrite code. You can create beautiful apps with lower effort.

Although Flutter is in a unique position of being able to target web apps designed for this new web generation, and there are also great achievements in Flutter development for desktop applications, we need to admit it may not be as effective as technologies and frameworks dedicated strictly to them. So each case of building web applications in Flutter needs to be considered separately.

You can also count on our experience and advice in web development in Flutter.

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