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What is Flutter and how to use it? The Ultimate Guide (2021)

What is flutter?
What is Flutter?

Every year mobile applications keep on gaining momentum, with millions of users preferring them for routine tasks. Correspondingly, the tools and technologies to support mobile app development are transforming too. Most of the traditional languages to build mobile apps offer the developers a complex approach to start with. However, the advent of readily available mobile app development frameworks had made this hazardous task easy to a great extent.

One such framework is Flutter that doesn’t only allow developers to build mobile apps but also makes them able to work across cross-platform, i.e., mobile apps can run across multiple platforms including web and desktops.

According to Stack Overflow insights, It is the most loved and wanted mobile app development framework, with 75% of developers expressing interest to use Flutter for cross-platform applications.

What is Flutter?


Launched in May 2017, Flutter is a free and open-source SDK for developing natively compiled applications. The software is written in C, C++, and Dart; it takes advantage of all the advanced features of these languages. The core of the Flutter software development kit (SDK) is suitable for mobile, web, and desktop platforms, using a single codebase. This exclusive cross-platform UI toolkit is often exploited by developers to build beautiful, fast, and scalable mobile applications for iOS, Android, Mac, Linux, Google, and Windows.

Currently, It is supporting over 50 million people worldwide. Probing further, Flutter’s preference as a cross-platform mobile framework has raised by 9% from 2019 to 2020 (in terms of software developer’s preferences) accounting for 39%, as per Talking about some popular apps built over Flutter, Google Ads (utility) and Alibaba’s Xianyu (eCommerce) are two notable examples.

Preference for flutter
Preference for flutter

Flutter- An extensible layered system

By default, the architecture of Flutter involves a series of independent libraries in an extensible layered structure. There is no access to the layer below for every layer lying above. And, the developers have the leverage to opt or replace every part of the framework level.


It is a modern and reactive framework written in Dart. Just like Flutter, Dart is also a product of Google that was released even before Flutter. Typically, app developers interact with Flutter via its framework. This framework generally constitutes a rich set of foundational classes (animation, gestures, and painting), rendering layers, widget layer, Cupertino & Material libraries.


The Flutter engine is at the core of the framework which is written in C/C++ and supports the lowest-level primitives (graphics, text rendering subsystems, and driving input) empowering all its applications. The developers can perform the low-level implementation of core API including text layout, plugin architecture, graphics via Skia, file and network I/O, accessibility support, compile toolchain, and a Dart runtime.


In Flutter, the embedder is platform-specific. For Android, Its Embedder is written in Java and C++; For macOS and iOS, Objective-C/Objective-C++ is used; For Windows and Linux, Flutter Embedder exploits C++. The application developers can utilize Flutter Embedder to integrate its code as a module in the existing application, or they can use the code as the whole app content. For commonly targeted platforms, It includes multiple embedders.

Developer’s workflow with Flutter:

Whenever the developers start creating an app with it, the entry point is provided by the embedder, which further initializes the engine. Further, ‘dart:ui’ is used to expose the engine to the framework, the command helps wrapping up underlying C++ code in Dart classes. Apart from engine initialization, the embedder is also behind the app lifecycle, including thread messages, platform messages, and input gestures (touch, mouse, and keyboard).

Relatively, Its framework is quite small and the developers require to implement high-level features in the form of packages. These packages are derived from a broader ecosystem, covering services such as animations, in-app payments, and Apple authentication.

Benefits of Flutter:

Free & Open-source

Flutter is a free-to-use open-source framework that makes it user-friendly and easily accessible. Being open-source also means that the developers can tweak custom features suiting to their projects or business or startups. Not only flutter but Dart is also free to use. Therefore, you can make an application of your taste with Flutter without any cost and permission hindrance.

Single Codebase

With Flutter, the developers are at complete ease as they don’t have to worry about writing multiple codes for different platforms. It offers you the facility of a single codebase that helps you build multiple apps for different platforms, including iOS and Android. Both look and feel of apps built with a single codebase of Flutter are just like Native apps.

Mild Learning Curve

Flutter toolkit is quite easy to learn. Not only experienced developers but newbies or non-technical persons can also learn to use it in no time. Just like Flutter, Dart also offers a mild learning curve to the developers. Basically, it is an OOP language that holds a resemblance to some popular programming languages, which makes it easy to grasp and use.

Skia- open source 2D graphics library

Another major benefit of using it is its own rendering engine, which makes Flutter a robust cross-platform framework. For rendering, Flutter offers Skia to render itself onto a platform-specific canvas. That means App UI built with Flutter doesn’t require UI adjustments while transferring it to a platform. It simplifies the app development process greatly.

Hot Reloading

Flutter app development is 1000 times faster than any other traditional approach due to its hot reloading feature, which increases development speed too. Hot Reload is a boon for developers as it allows them to view the changes applied to app code (simulators, hardware, and emulators) instantly. The altered code is reloaded in the fraction of seconds. There is no need to restart the app after every change in the code.

This, in turn, helps to add new features, fixing bugs, and building UIs quite easily. In case of any error, it can be fixed in no time and the developer can resume using the app instantly.

Highly Performant

Flutter is said to be highly performant as compared to its competitors. This is because of two main reasons: First, It is empowered with Dart that helps compiling into native code. Second, Flutter offers its own set of widgets that eradicates the need of accessing OEM ones. Eventually, the communication between the app and platform decreases while leading to fast app startup times and lesser performance issues.

Powerful Community

One of the most crucial aspects of using a framework is its backup developers’ community. During or after app development, there are fair chances of witnessing issues related to performance or code, etc. Thus, community support is helpful. If we talk about Flutter, it is constantly backed up by powerful community support.

Flutter offers extensively structured documentation, numerous real use cases, and other illustrations of Flutter’s implementation for cross-platform app development.

In addition to these benefits of Flutter, there have also been several updates in the previous year that have impressed the developers greatly. To name a few, Adobe XD support, Windows Alpha, Null safety, beta channel for Dart are some of the major updates of Flutter in 2020.

Having listed these benefits, let’s have a brief introduction to it’s downsides including fewer external 3rd party libraries (as it is new technology), large file size of apps built with Flutter, and need of learning new technology, i.e., Dart. However, It is still winning over the hearts of cross-platform app developers, which is easy to understand. The USA, China, Brazil, EU, and India are the top territories where millions of developers use Flutter monthly.

Helpful Tips to Use Flutter

  1. Use Flutter Snippets to create Flutter methods and classes in no time.
  2. Separate App’s logic class from widgets. Inject in-app code whenever required.
  3. Singleton Pattern to apply one instance with global point of access, for data reusability.
  4. Always use const Constructor to avoid Widget rebuild.
  5. Trailing Commas to format code via dartfmt.
  6. Utilize Spread operator of Dart 2.3 for clutter-free code.
  7. Follow DRY (don’t repeat yourself) approach to avoid duplicacy.
  8. Save type time with the Cascade Operator (when calling multiple methods).
  9. Split up widget trees into stateless widgets.
  10. Seek expert advice for advanced and complex projects.

Key Takeaway

Although multiple mobile app development frameworks come and go, It is a 100% promising technology with most innovative solutions in the market right now. For businesses looking to develop cross-platform applications, It is a great choice. Considering its core built and advantages, It may not be a universal remedy for every business, but it still offers great coverage and success in implementation.

If you are seeking apps with native experiences but don’t have enough time to get into native app development, Flutter is the most suitable option for you. You can build robust, cross-platform, secure, and fast-loading applications with a single codebase, which saves you a lot of time and cost.

For an in-depth project discussion and custom solutions, book a free business consultation with our Flutter experts. Our specialists have vast knowledge to discuss almost every topic on Flutter technology.

Author avatar
Manpreet Chahal
Manpreet Singh is an innovative mobile app developer with over 5 years of experience. To date, he has contributed his expertise and skills in various successful apps. He holds a tight grasp over trending technologies such as Java, Flutter, Kotlin, Android, etc. Listening to good music and spending time with friends are his two favorites apart from coding.
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