Flutter is more than a framework, and its capabilities extend beyond mobile. Learn about the pros and cons of Flutter for web development and find out how it can power your project.

Flutter is an open-source software development kit (SDK) for creating mobile, web, and desktop apps and an extensive UI library comprising tons of reusable elements, aka widgets.

As a cross-platform framework, Flutter allows developers to create software for different operating systems, including Android, iOS, Linux, macOS, and Windows, from a single codebase.  

Flutter's main strength lies in its ability to speed up the development process while delivering native-like performance, which puts it among the best solutions when costs and time to market are of the essence.

A brief history of Flutter: from mobile to web  

Flutter started as Sky – a Dart-based prototype framework developed by Google in 2015 to boost the screen refresh rate from then-standard 60FPS to 120FPS. The company wanted to facilitate designing high-performing apps, simplifying the effort for developers and providing users with a better experience. Flutter 1.0 was rolled out in December 2018 and quickly rose to prominence.

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According to Stack Overflow's 2022 Developer Survey, Flutter goes head-to-head with React Native as a top popular cross-platform framework used by professional developers. The framework has also been widely recognized by big tech and other industries. Companies using Flutter in their projects include Alibaba, BMW, Crédit Agricole, Google (obviously), eBay, Toyota, Ubuntu, and more.

Over the years, Flutter has evolved significantly, adding new features, and improving performance. One of the critical changes was the framework's expansion from mobile to multi-platform, including web and desktop, announced in May 2019 at the Google I/O.

Flutter for web: a browser-based experience from a shared codebase

Flutter for the web is essentially what it sounds like. It allows developers to create web apps using the same framework that was previously dedicated to building mobile software. As a result, it's possible to develop an application for iOS, Android, and web browsers from the same codebase, saving time, money, and effort. The difference is that for web experience, the Dart code compiles to JavaScript, whereas in mobile apps, it compiles to the ARM machine code.  

To provide web support for Flutter, Google implemented the framework's core drawing layer on top of standard browser APIs. The results are more than satisfying. With a combination of DOM, Canvas, and Web Assembly, Flutter can provide a high-quality user experience in most modern browsers. The framework works best for developing progressive web applications (PWAs) and single-page applications (SPAs), while it's less recommended for text-rich, document-centric services.

Pros of using Flutter for web development

There are quite a few reasons why Flutter is a top choice for thousands of professional developers. The most frequently cited advantages are related to Flutter for mobile, but some of them extend to web development. Using Flutter for designing browser-based software also has benefits of its own. Here are the main arguments in favor of leveraging Flutter to build a web app.

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One team to develop them all.

Since Flutter allows for multi-platform development, you don't need different expertise to deal with Android, iOS, and web-oriented versions of an app. One reliable Flutter team is enough to handle the process irrespective of the targeted platform. Again, this characteristic is crucial for delivering projects fast and cost-efficiently. Besides other expenses, it saves you the effort of recruiting  platform-specific developers.

Consistent UI design and animations across multiple platforms  

Consistency is a critical factor in UI design. Delivering seamless user experience across multiple platforms is a signature of professional front-end design. Flutter makes the work fast and much easier than in the case of platform-dedicated web development. Using a single Flutter codebase, developers can make sure that all elements in an interface look and behave the same way on any device, which contributes to the sense of familiarity and reliability in user experience. Obviously, the UI should be compatible with device-specific guidelines for optimal results.

Fast development with hot reload

Flutter is equipped with a hot reload function that immensely contributes to faster development. It's a feature allowing developers to instantly check the effects of alterations to the code without having to execute it after each update. You just need to enter "r" in the terminal window to get a view of the modified UI. The code changes are loaded into the Dart Virtual Machine, the framework rebuilds the widget tree, and the state of the application is preserved without rerunning the main (). With hot reloading, developers can quickly adjust the interface, fix bugs, and experiment with the design without worrying about precious hours ticking away.

Wide range of pre-built widgets and libraries for efficient development  

Flutter https://www.scoredigital.io/articles/an-intro-to-flutter-the-most-popular-google-framework offers an extensive toolset out of the box. The framework comes with a broad selection of built-in widgets and libraries, with many of them optimized for web browsers to make the app faster and more responsive. The availability of ready-made functional and visual components for creating buttons, icons, layouts, user input fields, etc., speeds up the development process and saves your team the effort of creating custom solutions. Flutter's widgets are highly customizable and can be adjusted to your vision and preferences. Notable web development features include Image Decoder API for image detection through the browser's built-in codecs, Lifecycle API providing better control over an initial load of a web application from a server-side HTML page, and support for progressive web applications (PWA). You can find tons of useful solutions in libraries on Pub. dev, the official package repository for Dart and Flutter apps.

It's based on Dart and thus easy to learn and use  

Dart itself counts among top Flutter's pros. This Google-invented general-purpose programming language is widely considered easy to learn and use. It's syntactically like JavaScript, so any skilled JS developer can be trained to code in Dart relatively fast and added to a Flutter project. Benchmarked against JavaScript, Dart is about twice as fast since it can be compiled ahead-of-time (AOT) and just-in-time (JIT), increasing Flutter-based apps' performance. The language also ensures high stability and scalability across projects. Finally, it boasts support from Google and comes with extensive documentation, which makes your projects easier to maintain and saves you the trouble of looking for answers elsewhere.

Cons of building a web app with Flutter  

Good as it is, Flutter is not free from flaws. The framework was primarily developed with mobile development in mind and upgraded for web support a few years later. The technology still evolves and has made significant progress since its inception, but there are a few limitations to be aware of.

Limited third-party library support compared to other web frameworks.  

Google is a solid guarantee of Flutter's quality. You can rely on the Big G for support regarding built-in packages. It's different, though, with third-party libraries. Neither Dart nor Flutter has developed a community comparable to that of JavaScript or, say, Python. As a result, some of the ready-made solutions you're interested in may be dropped by their authors at some point, leaving you on your own for necessary updates. In this regard, Flutter can't compare with React or Django.

Lack of support for some web-specific features, such as server-side rendering  

Flutter still lacks support for some web-specific features. A prime example is server-side rendering (SSR), which enables rendering an app on the server and then serving it to a client. SSR may slow down page transition compared to client-side rendering, but it's good for SEO, making it easier for crawlers to index pages by providing pre-rendered content as soon as the page loads. In the Pub. dev repository, you can find many web-oriented features available for use in your project. The trouble is many of them are third-party packages, which leaves you with the issue described above. Other web-related drawbacks include a lack of browser access to device features, like camera, microphone, and geolocation.

Potential performance issues when using Canvas for complex graphics and animations  

In Flutter, Canvas is a virtual surface for drawing, allowing designers to create shapes, pictures, visuals, and scenes. In web mode, it's used by default along with HTML and DOM to render a frame onto the web page as a tree of HTML elements. The DomCanvas approach, as referred to by the Flutter team, ensures the most compatibility across browsers, thanks to code brevity. It works well for applications with short-lived sessions that require fast startup but may fall short for long-lived sessions. There have been reports of difficulties in achieving cross-browser compatibility with Canvas-based animations and performance issues when using Canvas, such as degrading performance after a certain zoom level or problems with loading CORS images on CanvasKit renderer.

It's not the best choice for complex projects

Flutter apps are built with widgets that combine the business logic and presentation layers. The latter allows users to interact with the app, and the former – coupled with the infrastructure supporting the process – validates and transfers data. Such a combination is fine if the app is small and straightforward. For advanced projects, it's necessary to keep business logic and UI apart, in line with the separation of concerns design principle. Isolating logic from visuals reduces the number of dependencies between these layers, so changes made to one can affect the other to the least possible degree. Separation of concerns is a must in larger projects, as it facilitates change implementation, parallel development, and maintenance. There are ways to decouple business logic and UI in Flutter, but some of them are overcomplicated, so you need to go the extra mile to find the best approach for your project.

How does Flutter compare against other web development frameworks?

Flutter has gained immense popularity in the mobile segment, but it's also attracted recognition from web developers. Still, it faces strong competition from other leading front-end development frameworks, including React.js and Angular. Voices in the never-ending discussions on the pros and cons of specific technologies vary depending on individual preferences, experience, and expertise. One of Flutter's advantages over Angular or React is that the former is a full-blown UI toolkit rather than a "mere" collection of libraries. Flutter's key strength lies in a robust set of out-of-the-box widgets that take a lot of burden off developers, who can focus on personalizing ready-made elements instead of creating them from scratch. As regards downsides, Flutter is not recommended for text-heavy apps due to its SEO-related limitations. It's also been criticized for performance issues involving transitions, scrolling, and animations. Both React and Angular share some of Flutter's advantages, such as hot reload (React) or a rich assortment of built-in tools (Angular). Compared to React, Flutter for the web enables more efficient cross-platform development but boasts a smaller community. Compared to Angular, Flutter offers faster apps at the cost of lesser stability. There are many more factors to include in a detailed comparison. The particularities, however, depend on a given project's technical requirements and business goals.

Flutter for the web is evolving rapidly. Find out if it will work for your project!

Flutter for mobile has made it to the top framework league, and Flutter for the web is quickly following suit. Attended to by Google, it evolves rapidly and adds new features. Recently, the management behind the project announced new improvements contributing to faster application load time, better integration with traditional web experiences, and more advanced visual effects for web apps. With the evolving Flutter ecosystem, the number of Flutter-powered websites has more than doubled in less than a year, contributing to the growth of the framework even more. Wrapping it up, Flutter is a fully operational technology that can be leveraged for streamlined web development. If you want to find out if it will work for your project, reach out anytime – we'll be happy to dig into the details.

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