Promptless AI is here soon - Production-ready contextual code. Don't just take our word for it. Know more
Know More

Your Go-To Guide on How to Deploy Flutter Web App

No items found.

Nidhi Sorathiya

August 11, 2023

Nidhi Sorathiya

August 11, 2023

As a passionate developer, I've always been fascinated by how technology constantly pushes boundaries. Recently, my interest in the Flutter SDK has grown exponentially due to its promising capabilities. Through this blog post, I aim to simplify the process of how to deploy a Flutter web app, specifically geared towards developers with an existing understanding of Flutter app development.

When I first encountered Flutter, developed by Google, I was instantly drawn by its ability to create natively compiled applications for mobile, web, and even desktop from a single codebase. This powerful capability offered by Flutter helps in taking application development to another level.

Origins of Flutter

Flutter SDK, an open-source UI software development kit, was unveiled to the world by Google in 2015. Since its release, it has been fulfilling its aims to develop beautiful and highly efficient applications that feel natural across different platforms. Not to mention, its vast catalogue of widgets and tools makes the development process a delight!

Your Go-To Guide on How to Deploy Flutter Web App
Flutter for efficient app development

Brief on Web App Development using Flutter

Developing web applications using Flutter is a seamless experience. Flutter's web support provides a browser-based platform for deploying existing Flutter code written in Dart. It's especially appealing as it offers excellent performance and allows code reusability. Getting started with web development in Flutter is extremely straightforward.

Preparing your Flutter web app for release

Being a Flutter developer, it's significant to understand that the preparation phase is crucial before we take the final plunge to publish our app. This phase ensures that our app performs well when the user interacts with it.

Why must your Flutter app be ready for release?

When we're developing an app, mostly, we're occupied with writing and testing our code in a debug environment. But the debug version of the app isn't streamlined for optimal performance. So, switching to the release version will not only enhance your app's performance but also prepares it for deployment on a server or a host.

Building the release version using flutter build web command

To pull this off, we use the Flutter build web command which helps create a release version of our Flutter app. For an added advantage, we can also select the type of renderer we wish to use with the --web-renderer option.

Here's an example:

Understanding the release build structure

Once you run the command, the release build of your Flutter app is generated and all the necessary assets and files are located in the /build/web directory of your project.

Testing your Release-build Flutter Web App

Once your web app is ready for release, carrying out a test run is always a prudent choice. It helps verify the app is functioning as expected before you proceed with the actual deployment.

Launching a Local Web Server

To begin testing, we need a web server (you could use SimpleHTTPServer in Python or dhttpd package). Running a web server will host your web application locally, allowing you to interact with it in an environment similar to a real user.

For instance, if you have Python installed on your system, here is how you can start a simple server:

This command starts a server on port 8000.

Viewing your app using localhost

Next, you need to open your web browser and navigate to localhost on the port where your server is running. For the example we used, you need to go to localhost:8000. There, you'll find the released version of your app, ready to be interacted with.

Now, our app has been built and tested, it's ready for its next journey – Deployment!

How to Deploy Flutter web app on different hosting platforms

The next phase of our journey is finding a good home for our app, which, in technical language, is known as deployment. Deployment can be defined as making our Flutter web app available to users by hosting it on a server.

What is deployment?

Deployment refers to the process by which the application is made available to the end-users. It's akin to opening the doors for the users to come and explore your app. This is where we bring into play the concept of servers or hosts.

Firebase hosting

Firebase provides a great hosting platform for our web apps. It's tough to go wrong with its superb features, such as fast content delivery, easy-to-use functionality, and SSL protection on all Firebase Hosting sites.

To use Firebase hosting, you need to first install the Firebase CLI tools via npm:

Initialising Firebase for your app

Firebase offers a CLI that is extremely manageable and integrates well with Flutter. To engage Firebase with your Flutter app, use the Firebase init hosting command followed by a series of simple steps:

Deploying an app to Firebase Hosting

Once Firebase is set up and integrated with your app, the next step of the journey is to deploy the app using the Firebase deploy command. What's more convenient is that this command runs the flutter build web --release making your deployment process run smoothly:

Other hosting platforms (GitHub Pages & Google Cloud Hosting)

Firebase is definitely not the only home out there for our Flutter web app. Multiple other options, like GitHub Pages and Google Cloud Hosting, can also be considered while deploying your app.

Handling Images in Your Flutter Web App

Now that you're familiar with the deployment process, let's discuss another integral aspect of web app development - handling images. The probability of a web app without images is quite slim, so understanding how to handle them is important.

In Flutter, the standard way to display images is using the Image widget. It's crucial to note that due to the inherent design of web browsers, we often have some specific restrictions when handling images.

Understanding Image Widget

The Image widget in Flutter makes image management somewhere between easy and enjoyable.

You can load an image in your Flutter web app using the widget in just a few lines of code.

This piece of code fetches the image hosted on the provided URL and displays it in your app.

Limitations and Protections in Web Browsers

Image handling is slightly different in web development due to the restrictions used by web browsers to run untrusted code while ensuring no harm comes to the host computer. These limitations, while necessary, can often limit what you can do with images compared to mobile or desktop platforms.

Choosing the right Web Renderer

As a Flutter app developer, understanding the differences between various web renderers is essential. The choice of web renderer has a profound impact on the app's performance and the final user experience.

Choosing web renderer for high impact app performance and user experience

By default, Flutter uses the auto choice for web renderer. This versatile default option means that your app runs with the HTML renderer on mobile browsers and CanvasKit on desktop browsers. It essentially optimizes the use of renderers based on the platform.

Understanding the auto choice

The auto option for the web renderer is an intelligent setting that varies the renderer based on the platform. This is significant since different platforms may have different capabilities and demands.

For instance - while mobile browsers value a smaller download size, desktop browsers have the resources to leverage a larger, faster renderer written in WebAssembly (like CanvasKit). Therefore, adopting the auto choice for your web renderer can prove beneficial in providing an optimized experience to the end user.

Optimising Renderer Choice for different platforms

Should the need to specify a particular renderer arise, it can be done using the --web-renderer option mentioned earlier in the post. The default, as we now know, is auto, but there are two more options: can canvaskit and HTML.

So, when you find that one renderer provides a superior user experience for your particular app, you are entirely free to specify that in your Flutter build command.

Minification process in different types of Web App Builds

Minification is another essential aspect of deploying web applications. It plays a crucial role in optimizing your code for production use, thereby enhancing the app's performance.

Brief on Minification

In the simplest terms, minification is the process of removing all unnecessary characters in the source code without changing its functionality. These unnecessary or redundant characters usually include white spaces, line breaks, comments, and block delimiters, which are useful in development but unnecessary for execution.

Code Minification and Tree Shaking Performance on Debug, Profile, and Release Builds

In Flutter, the process of minification is processed automatically for you when you build a release version of your web app. Here's an interesting fact: Flutter performs minification differently for different types of builds—debug, profile, and release.

In a Debug build, neither code minification nor tree shaking is performed. In contrast, a Profile build performs tree shaking but not minification. However, a Release build performs both minification and tree shaking, thereby providing an optimized and performance-efficient version of your app.

Embedding Your Flutter Web App into an HTML page

So, our Flutter web app is now ready and minified for optimum performance. The next step is to make it accessible to users, which could be on a website in the form of an embedded app within an HTML page. There are two main ways to do this: using a host element or an iframe.

Using hostElement to specify target element

To allow our Flutter web app to understand where it needs to render within a larger HTML file, we use the hostElement parameter. The initializeEngine function within the Flutter engine takes this hostElement param to bind the app to a particular div in your HTML.

For instance, consider the following code:

In the above code, the Flutter web app is set to render inside the div with the ID "flutter_host".

Running a Flutter app from within an iframe

An alternate method to host a Flutter web app within an HTML page is by using an iframe. An iframe allows us to nest the Flutter app as if it's just another webpage.

Here's a skeleton of the code needed to incorporate an iframe into an HTML file:

Replace "URL_to_your_app" with the actual URL where your Flutter web app is hosted.

Progressive Web App (PWA) Support in Flutter

Progressive Web Applications (PWA) are one of the most exciting technologies of recent times. They enable developers to build web apps that feel and behave like native mobile apps. The support for PWA in Flutter adds another feather to its cap.

PWA features in Flutter

Starting version 1.20, Flutter provides basic support for PWA right out of the box. So, when you create a new Flutter web app using flutter create, it equips your web directory with a default manifest.json file. This file contains necessary metadata about your app and signals your Flutter web app as a PWA that can be installed by users.

Creating PWA apps using Flutter

Creating a PWA using Flutter involves a few steps more than traditional web apps. However, the Flutter build web command per default considers your Flutter app as a PWA.

Behind the scenes, the build process generates a flutter_service_worker.js file. This service worker is a script that your browser runs in the background. It's responsible for fetching the essential resources for your web app and caching them for offline usage, hence making your web app installable and offline-capable.

While the PWA support in Flutter is promising, it's still considered a work in progress. However, the Flutter team is working relentlessly to improve it, so keep an eye out for future updates and enhancements!

Evolving as a Flutter developer: Master the Art of Deploying Flutter Web Apps

Just like any good journey, this exploration of how to deploy a Flutter web app has been filled with learning and insights. We’ve traversed the paths of building the app for release, testing it, deploying it to a host, handling images, choosing a web renderer, understanding code minification, and embedding the app in an HTML page, Finally, we arrived at the exciting possibility of creating Progressive Web Apps using Flutter itself.

Your Go-To Guide on How to Deploy Flutter Web App
Deploy amazing Flutter Web Apps

Recap: Deploying Flutter Web Apps

The clearest takeaway from our journey is how Flutter simplifies the process of web app development, from writing the code to preparing for release, and finally to deploying to a server. The skill of deploying a Flutter web app isn't just about knowing the commands or the steps, but also about understanding the process and making the right choices.

I hope this guide has helped clarify deploying Flutter web apps. As Flutter developers, we're always keen to iterate, improve, and learn. Happy coding and deploying!

With that, I conclude this guide on how to deploy the Flutter web app. Enjoy the process of creation, and remember, each line of code is a step forward, irrespective of the challenge it brings.

Frequently asked questions

Q: How do you build and release a Flutter web app?

Building a Flutter web app for release is done using the command flutter build web. This command prepares a release version of the app and places it in the /build/web directory of your project.

Q: How do I deploy a Flutter web app on Firebase?

To deploy your Flutter web app on Firebase, you first need to install the Firebase CLI. After the Firebase CLI has been installed, run firebase init hosting to initialize Firebase for your app. Answer the series of questions that follow. Finally, execute firebase deploy to upload your app to Firebase Hosting.

Q: How do I deploy a Flutter web app on my own server?

If you want to deploy a Flutter web app on your own server, you need to first build it for release using flutter build web, and then move all the files from the /build/web directory to the location on your server where your website's files are stored.

Q: How do I run Flutter web on a local server?

To run your Flutter web app on a local server, you need to start a web server by running a command such as python -m http.server 8000 in your terminal. Then, open your web browser and navigate to localhost:8000 to view the release version of your app.

Q: How do I deploy a Flutter web app to a cPanel server?

Deploying a Flutter web app to a cPanel server involves building your app for release, and then uploading the files present in the /build/web directory to your cPanel's public_html directory. You can achieve this using the cPanel's File Manager or any FTP client.

Frequently asked questions

No items found.