What is Flutter Web Deploy and How Does it Work?

Hermione at Pangea.ai
Ian Deed
Published: 14.10.2022

The Flutter framework, Google's flagship UI tool for creating cross-platform applications, is now more capable, more productive, and more broadly applicable than ever before. Initially launched as a tool for creating UX-focused mobile apps, Flutter has grown to do so much more for teams in a short amount of time. Flutter web deploy tooling is just one example of an under-used feature set that can help development teams reach a broader audience with truly remarkable applications.

Despite the Flutter platform still commonly being thought of as a mobile-first environment, the reality of modern Flutter is that it's just as easily capable of targetting desktop environments through Linux, macOS, and Windows as it is on the web and mobile platforms. Flutter has even grown to become the first-choice technology for developing applications for the Google Fuchsia operating system.

Our top-rated Flutter development companies regularly deploy the technology to each of these environments in addition to smart devices, automotive platforms, and emerging technologies that are becoming more prevalent every day. When it comes to solving real-world challenges with attractive, user-friendly applications then it pays to lean on one of the highest quality front-end frameworks currently available.

Today, the Flutter platform has a broad range of available targets and an abundance of tools and resources to help developers reach them. So how do we use Flutter web deploy to target web-based applications and how effectively can the tooling be used to reach an audience on the web?

Flutter's Cross-Platform Architecture

Flutter is somewhat unique amongst cross-platform frameworks in allowing exceptionally high degrees of code reuse between vastly different operating environments. While most frameworks aim to achieve this goal, it's not uncommon to require up to 50% additional code when reusing code on a second, third, or fourth platform.

Flutter achieves a high degree of code reuse by handling many system functions and operations internally. Yet, despite doing a lot of its own heavy lifting when it comes to rendering animations and interfaces, Flutter also allows developers to interface directly with the target platform with ease.

Architecture decisions that separate the platform into distinct layers responsible for rendering, event handing, and system management allow user code to be isolated from platform-specific functionality. It's this unique Flutter design that is one of the primary reasons the framework consistently appears amongst our top application development frameworks time after time.

Flutter Architecture Diagram showing Flutter's layered architecture, with Framework, Engine, and Embedder tiers.

Source: Flutter architectural overview

For developers, this layered architecture model provides a framework layer that can be written to once and readily ported between one technology and the next. It's this framework layer that developers typically interact with and one of the primary reasons that Flutter is often referred to as merely a framework despite offering so much more to teams.

While the framework layer offers a lot for developers to build from, Flutter's framework is comparatively small next to some of its competitors such as React. Common external features that developers may want to deploy for applications are often accessed through packages, plugins, and libraries available through Google's official package repository.

Flutter Web Deploy Architecture

Deploying existing Flutter code to the web is as simple as adding one more additional target to your projects. Flutter web deploy can simply add one of many available browsers to your list of development targets and deploy to a hosting target in the same way as a mobile app or desktop executable file would be packaged.

When targetting the browser, Flutter compiles its code to JavaScript instead of the JIT (just in time) or AOT (ahead of time) compilers commonly used to generate Android, iOS, or desktop packages.

While this shift in how applications are compiled seems like a significant departure from conventional Flutter apps, Dart is heavily optimized for compilation into JavaScript as this was the primary use case of the language when it was first built over a decade ago.

The platform's unique rendering engine, written in C++, is less well-suited to being ported to JavaScript. To solve this issue, Flutter provides a re-implementation of this engine to ensure cross-platform functionality works as intended.

The Flutter web deploy platform provides both Canvas and WebGL rendering options to allow developers to optimize between application size and overhead, better graphics performance, or some combination of these two factors.

Flutter web deploy architecture chart with Framework and Browser tiers.

Source: Flutter architectural overview

The biggest change that Flutter web deployment introduces to apps is a shift from Flutter's Dart-based runtime to compiling applications directly to JavaScript instead. While some subtle changes do exist it's vanishingly unlikely that developers will run into code that changes between one platform and the next.

Our ultimate guide to Flutter development takes a deep dive into the details of developing Flutter applications within your engineering teams.

Advantages of Flutter Web Deployment

Knowing when and where to use Flutter for the web is just as important as knowing how to use it practically. The decision on where to deploy Flutter for any of its available targets comes down to recognizing the advantages and drawbacks each approach can deliver for your project.

Here we take a look at some of the key things that Flutter web deployment enables in our software development teams.

Re-use Existing Code to Target More Users

One of the biggest boosts that Flutter web deployment can provide for teams is in enabling existing code to be re-purposed for more platforms and use cases than initially intended. With a complete production-ready app already deployed to the marketplace, all the legwork of design, development, and testing has already been completed to a high standard — why not re-use that effort to deploy to the browser too?

sing Flutter's web deployment toolchain can open up additional ways for users to interact with the app, help find a new audience on the web, and bring the app to additional platforms with browser support.

Typically, only minimal UI tweaks and considerations have to be made to bring an existing mobile or desktop app to the browser.

Design for a Broad Range of Targets

With the tools and libraries currently available, your teams can develop applications from the ground up to target Linux, macOS, Windows, Android, and iOS all from a single codebase.

Approaching application design and development with this in mind allows designers and developers to fully consider the different methods of user input needed, UI changes required, and the platforms to test on before launching the app. Being able to work on a unified codebase for a multi-target project allows developers to focus on the differences between platforms and ensure the UX is effective and consistent across the board.

Exceptional Native Web Apps

Up until now, many development teams have focused on the use of Flutter web in scenarios where there's a companion mobile application to consider too. Flutter's web tools and technologies are now sufficiently capable and performant enough that they stack up against many of the best web frameworks available today.


Even where there's no parallel desktop or mobile project to consider, the advantages of Flutter web tools make the technology well worth considering for a stand-alone web project. These advantages include:

  • Flutter's exceptional rendering capabilities for creating interfaces, animations, and user interactions.
  • Remarkable application performance capable of rendering web apps at 60fps with ease.
  • Ability to import JavaScript libraries and tools from within Flutter Web.
  • Provides a large array of Flutter-specific libraries through Flutter's unique package manager.
  • Comes bundled with both Google's material design and Apple's Cupertino elements for bespoke application design.

Of course, each technology solution comes with both advantages and drawbacks that have to be considered against competing options to arrive at the best approach for your project. Similar to the approach we took when considering the best cross-platform mobile tools in analyzing Flutter vs React Native — we need to analyze the drawbacks to Flutter web deployment too.

Some of the most notable drawbacks to Flutter for the web include:

  • Flutter creates large web apps in comparison to many other technologies. This comes as a result of bundling the full Flutter framework into web apps. As a result of outsized application sizes difficult for Flutter-based apps to compete with other web tools.
  • Flutter's web tools suffer from poor SEO performance from the start. If content and design aren't addressed well by teams, Flutter web apps may suffer in search rankings
  • Developers cant readily modify the JavaScript compiled from Dart. This can have impacts on overall application performance that is difficult to resolve.
  • Some plugins may not be fully supported by Flutter's web technologies yet.

How to Run Your Flutter App On The Web

Flutter web deployment has been available as a stable release since Flutter 2.0. If you plan to deploy an existing Flutter app to a web target then you should ensure you're using a version later than that. Now on version 3.0+, several tooling and performance improvements make updating to a modern version well worth the time and effort.

To update to the latest version of Flutter you can use these two commands in the terminal:

flutter channel stable

flutter upgrade


You should see the browsers you have installed included in the devices list of your IDE. Each browser is available as a device target to build for in deploying for the web. To configure and build your existing app for the web, simply enable the web using the Flutter config command.

flutter config --enable-web

flutter create .

Your app should be built with a web target enabled. The next thing to do is to host and run your application in a browser. To run your application from localhost using Chrome as your primary device, simply use:

flutter run -d chrome

Your existing Flutter app should be running and available to debug, develop, and test on your local machine. The next step to production is hosting your solution through Firebase or some other third-party service.

Factors to Think About When Designing Flutter Web Apps

The technology hurdles between physically transforming your Flutter application into a solution to be hosted on the web are relatively trivial to overcome. You could take any Flutter app you have in your repository, run the commands listed above, wait for an extended first build, and deploy it to production in less than five minutes.

Good design and development practices dictate that there's more to deploying an application as a professional software developer, however. There is a range of technology, UI, and UX decisions to be made to ensure your application is performant, reliable, and delivers a high-quality user experience to the audience it reaches.

Some key things to keep in mind when designing cross-platform apps for the web include:

  • Checking if your current Flutter plugins support web deployment. As we've addressed in the drawbacks of Flutter web, not all of the Flutter plugins developers depend on support use on the web yet. It may take some time to add web support or find alternative ways to approach the challenge.
  • Consider application layout, widgets, and menus for varying screen sizes and user experiences. Building for the web means building for a wide range of devices that includes desktops, smart TVs, and unexpected platforms. It's good practice to ensure your apps work well across almost all use cases.
  • You should consider alternate modes of interaction too. A user may prefer to use a keyboard and mouse, touchscreen controls, or voice input as needed. Accessibility concerns should be first and foremost on your UI priorities to ensure all users can use your application.

Modern Flutter Web Deployment

Flutter web adds an exceptional amount of value to a platform that was already immensely valuable to developers. By building single-page applications using Flutter resources, web deployment adds a large number of devices and targets to the already impressive list development teams have available.

If you're already considering extending the breadth or depth of your Flutter applications using Flutter web tools then it's very likely to be an option well worth taking.

FAQs:

Q1. How do you deploy a Flutter web application?

Building a Flutter web application is as simple as running the terminal command 'flutter build web'. In many practical ways, Flutter views the web as just one more device target that code can be deployed.

If you're using an older version of Flutter you can update to the latest version using the two terminal commands:

flutter channel stable

flutter upgrade

Next, you should enable the web as a target on your Flutter install using the command:

flutter config --enable-web

When you run your web app you will need a host to serve the project to clients. For developing and debugging Flutter web code you can use localhost to serve code from your own machine, making and viewing changes in real time. To do this using the Chrome browser, simply run:

flutter run -d chrome

This will launch your Flutter app in the [development compiler](https://dart.dev/tools/dartdevc in Chrome.

Q2. Is Flutter good for the web?

Yes, Flutter is an excellent choice for development teams looking to build reliable and performant single-page apps. One potential drawback to Google's platform is that compared to larger, more mature, and more robust toolsets such as Angular — Flutter is slightly lacking in outright performance and customization. However, Flutter more than makes up for these shortcomings in the modern tooling, ease of use, and UI capabilities it enables within teams.


For teams that have experience, knowledge, and a codebase in Flutter already then the choice to extend the tool to development on the web is an easy one to make. Flutter excels at creating user dashboards and attractive user experiences in a way that few other tools can match.

More complex web apps that require extensive navigation components, complex and unconventional UX requirements, and vast numbers of pages may be better served by another type of solution, however.

Q3. Is Flutter web stable now?

Yes, Flutter's web deployment tools are now available on the platform's stable channel. First introduced to stable release in March 2021, the technology is beginning to reach a more mature stage where expertise and knowledge are more commonly shared amongst developers.

In the year since Flutter Web was moved into a stable release, the technology has been used to create many significant web apps such as Rive and Supernova.

In Flutter 3.0 and beyond, Google has unveiled a significant number of platform updates, revisions, and upgrades based on developer feedback. Today, the platform is more refined than it was in 2.0 with more consistent UI and application behaviors that closely match mobile and desktop applications.

Future updates to Flutter web are likely to build on this progress as developers gain experience, expertise, and confidence in using the technology to deliver PWAs and SPAs.


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