Flutter is a software development kit and UI framework from Google that aims to make developing beautiful mobile apps faster and easier. With Flutter, you can build modern, high-quality apps for Android, iOS, and future platforms using a unified codebase. Flutter apps run blazingly fast, look great and are fully functional on all major mobile platforms. 

Google’s Flutter also has powerful developer tools, such as a code editor, interactive widgets, and performance profilers, that make it easy to build high-quality apps. In addition, Flutter offers unique functionality to help developers with the most mundane task. So, Google has made it possible for companies to leverage Flutter with their existing native app without writing the whole codebase in Flutter all over again.

Convert your existing Android or iOS app to Flutter quickly

Flutter is Google’s brainchild and an open-source, cross-platform framework. It is highly flexible and allows developers to build a scalable, robust & fully functional cross-platform app. In the year 2019, Flutter released the add-to-app functionality. This functionality empowers us to embed the whole Flutter app or parts of the app into an existing iOS/Android app. 

Simply put, you can migrate your iOS/Android app into Flutter seamlessly without compromising on performance. Even our team has leveraged this feature to convert an existing application to a Flutter app. And in this blog, we will be talking about Kody’s developed milk delivery application written in Android.

The application aims at satisfying the daily dairy needs of the customers. We formed a team of developers who worked vigorously to deliver a Flutter version of this application. Noteworthy, we didn’t do the transfer haphazardly; we deliberated the cases and then decided to convert to Flutter.

Scenarios When Converting Your Existing App To Flutter Is The Most Fruitful

  1. When you have an already existing application in either Android or iOS, and it is due for an update.
  2. Your existing application is facing technical issues, and you, anyhow, have to work on releasing an update.
  3. When you wish to go with the trend and wish to release a fully-functional application.

In the case of our milk-subscription app, we first developed a native web app as a Proof of Concept. Later, with the success of this app, we planned a native android app. And gradually, the client demanded to convert to Flutter.

We wish that our Flutter app looks unique and delivers a user experience to remember. It is pretty obvious that the massive code base and variety of technology stacks might tempt you to make a swift move to Flutter.

Why we chose Flutter is because of the following reasons:

  • Its ease of development;
  • The speed and performance of the Flutter-developed app;
  • Two apps with a single code;
  • The application needs to be tested only once.
  • It is a modern framework providing all the required features & functionality for swift mobile app development.
  • The Hot Reload feature allows us to instantly view the changes made in the source code.

You might have your own set of problems that you wish to solve using Flutter. So, discuss how they wish to proceed with the Flutter solution with your client and team.

Moving ahead with the topic,

How to transfer your existing app into Flutter?

To begin with, you need to integrate Flutter as a library or module. That module is responsible for reflecting the application’s UI. You can create a module using Flutter create-t module command. This will initiate a new project creation yet with a bit different structure.

By creating a module in this way, you can separate the main code from the Flutter code. This module acts as an external dependency.

The further course of action that we followed is the same as described in the official Flutter documentation.

Add Flutter to an existing Android app:

1- Open existing project

2- New Flutter module wizard

3- Use Flutter Android APIs

4- Build & run

5- Attach & hot reload.

convert existing app to flutter

Things that Flutter allows us to do when integrated into Android apps.

  • You can add a Flutter SDK hook to your Gradle script to auto-build and import the Flutter module.
  • If you want to integrate the Flutter module into your own build system, build your Flutter module into a generic Android Archive (AAR) that also better Jetifier interoperability with AndroidX.
  • Use FlutterEngine API for starting and continuing your Flutter environment independently.
  • Module import/creation wizard allows you to co-edit Android and Flutter projects in Android Studio.
  • It supports apps built with Java and Kotlin.
  • Flutter plugins can be integrated into the preexisting platform and used for Flutter modules to interact with the platform. 
  • Using the Flutter attach function from an IDE or the command line, you can connect to an app that contains Flutter and debug it or reload it using a stateful hot reload.

Add Flutter to an existing iOS app:

1- Open existing project

2- Create Flutter Module

3- CocoaPods Install

4- Use Flutter iOS APIs 

5- Build & run

6- Attach & hot reload.

Things that Flutter allows us to do when integrated into iOS apps.

  • Add a Flutter SDK hook to your CocoaPods and Xcode build phase to auto-build and import the Flutter module.
  • It allows you to create a Flutter module into a generic iOS Framework so that you can integrate the module into your own build system.
  • FlutterEngine API is for starting and persisting your Flutter environment independently of attaching a FlutterViewController.
  • It also supports both types of iOS apps, Objective-C and Swift.
  • Let Flutter modules use Flutter plugins to interact with the platform.
  • Using the Flutter attach function from an IDE or the command line, you can connect to an app that contains Flutter and debug it or reload it using a stateful hot reload.

Our experience in converting an existing app into Flutter

Here is the series of screenshots of how our application looked when natively developed and how it looks with Flutter. If you do not wish to do it yourself, you can also hire our Flutter developers to initiate your transfer.

Native Android Application.:

convert app to flutter

Flutter Application:

convert ios and android app to flutter


As you can see above, the application developed using Flutter looks more crisp and accurate than that developed using the Android programming language. It was quite speedy for us to make this quick move to Flutter. The Hot reload feature and Ahead of Time compilation feature made it easy for us to transfer our client’s app to Flutter.

If you need any further knowledge about Flutter app development, you can always connect with us. We are one of the early adopters of Flutter, and that makes us nimble in this industry. In our opinion, Flutter is the future, and it is the best time to start developing an app using Flutter.

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