Building a Full-Fledged Chat App in Flutter with Firebase

Nowadays, chat apps have become an essential part of people's day to day life. There are so many popular chat apps like Whatsapp, Facebook Messenger, Line, WeChat, and more used worldwide.

Do You Know?

WhatsApp, Facebook Messenger and WeChat are top 3 chat apps which have around 4 billion active monthly users.

Chat apps like WhatsApp generated $49 million in revenue in 2015 and will rise to $4.8 billion in 2020.

Viewing these messaging apps related stats, I can say that chat apps will be one of the future trends of the business, and this will accelerate the business growth in the upcoming time.

Now the question arises “ how to develop a highly functional chat app and what technologies should businesses prefer to develop popular chat apps?”. 

The answer to this question is simple by using Flutter with Firebase one can build leading chat apps.

If you want to build a leading chat app like WhatsApp, Telegram or WeChat, then I will recommend you to choose Flutter with Firebase as this will help you develop a full-fledged chat app right from scratch, and it can be released on Google Play Store and iOS App Store.

Let's talk about how businesses can build a chat app in Flutter with Firebase.

Essential Steps To Build Chat App In Flutter With Firebase


This is one of the essential parts of any Firebase chat app as this keeps your data secure by quickly signing-in the app with your username. So let's move further and understand how to create a Google sign-in.

If you are preferring the Google Sign-in option, then you can use CMD/terminal, or VS code; these all will work as a streamlined code editor and offer support for development services like debugging, version control, and task running.

Thereafter straight jump off all the comments in the main.dart and get rid of MyHomePage() stateful widget and form a folder inside the library.

Try to build all screens in the given mentioned folders and also save the file with different names.

  • Singup.dart

  • Singin.dart

  • Chatroomscreen.dart

  • Forgetpassword.dart

After ordering all the images with different names, produce a widget called Sign-in inside the Sign-in.dart, where you can use scaffold, appBar, body and floating operation buttons.

After doing so use the "import 'package:Flutter/material.dart';" for sending the files to AppDelegate.h.

Thereafter start the cloud Firestore and storage and after that enable sign-in method with Google.

By making use of the import link, one can quickly move the files to the app delegate and cut down the danger of manually editing or adding any data at Firebase.

Doing this first step will get completed!


By integrating the right set of plugins, you will be able to build a leading chat app using Firebase.

For installing the plugins follow the instruction of adding “Firebaseauth, googlesignin, cloudfirestore, Firebasestorage” to the chat app. If in case you are finding challenges in adding plugins, then you can hire Flutter app developers; this will help build an impactful chat app. 

Well if you are building a Firebase chat app that login via Google Account, then consider the below-mentioned plugins. These plugins will offer you user info, real-time data for messaging and uploading a picture.

Ideal Plugins for chat app development:

Image Source: 


Image Source:


In the ideal chat app, multiple screens are present; it includes registration screen, login screen, setting screen, homepage screen (main screen) and chat screens. All these screens are built by writing different sets of codes, and that's why it's important to follow the necessary instructions. 

  • Layout Of The Login Screen

Once a user sign-in the chat app successfully, the return variable FirebaseUser includes some essential information of the user such as displayName, PhotoUrl and more.

Image Source: GitHub

On entering the login screen, the user has to verify whether it is a new or already existing user and this is done by just placing a query to the server. If it's a new user, write it to the database.

Image Source: GitHub

Additionally, the user needs to write the info in the local storage and navigate to the home screen when login successfully.

  • Layout Of The Main Screen

In the main page of the chat app, the list of the available user name is mentioned, and additionally, it also showcases the user's complete information, including about me, nickname, and avatar. Well, you can also design the page and add users other information.

View how you can list users by utilizing StreamBuilder. Look codes example for further assistance:

Image Source: GitHub

When the user touches the back button from the main screen, then it will exit the app, but before that, the app should show a dialogue box to confirm, like this:

In order to catch the back event, use the WillPopScope widget, it provides an attribute named onWillPop when the user touches the back button, it goes to this function first, and at this function, dialogue box window gets opened.

The main screen of the Flutter chat app should also contain setting alternative like this:

Coding example

Image Source: GitHub

  • Layout Of The Setting Screen

This page allows users to edit personal info like switch avatar, nickname and about me. The users are also provided editing access to additional fields.

Firstly load current user info from the disk that the user wrote at the time of login. It will look like this:

If in case a user wants to modify the avatar, then you need to upload a file to Firebase Storage, and this will offer the file’s URL. Thereafter, new photoURL needs to be renewed to Cloud FireStore. Always remember the file name that you have set for the new file as Firebase automatically displaces the old with the new one.

This task requires a lot of coding, but it can be easily completed by availing Flutter app development service from the best software development company.

  • Layout Of The Chat Screen

The chat screen is an area where users can send and receive text, files, images, and more. It means the chat screen will be handling multiple things.

In order to start with the chat screen part, we first need to layout root widgets (UI) like this:

Image Source: GitHub

The root is WillPopScope as you need to manage the back press. In case, the sticker or keyboard is displayed, then you need to hide it rather than navigating it to the initial screen.

The second thing which is important is sending stickers in the chat. Usually, when the sticker appears, then the keyboard disappears. So you just need a variable that is ShowSticker to identify whether the app should display the sticker or not. Additionally, focusNode will aid you to control the focus on the text input.

Thirdly, to load previous texts and to monitor to new incoming texts, it is advised to use StreamBuilder, like this:

Image Source: GitHub

Fourthly, how to handle the message load? If the user sends the image, you just need to upload the image and get the URL. After that, just add the content of the message along with the URL. When the app receives new messages firstly, you are required to verify the type of text. If it is the image, then you need to load the image from the network and if it is a sticker, then show it from the local file.


After successfully completing the layout part of the various screens, you are finally ended with the final structure utilizing Google Firebase firestore. 

Final Words

The steps mentioned in this write-up will help you develop a chat app in Flutter with Firebase. However, completing these steps might not be simple as it sounds because on working with the coding part, multiple bugs occur. Few bugs beginners can resolve, but few are really hard to handle, and for that, we need an experienced person. 

flutter app development, flutter app, chat, application development, firebase cloud messaging, firebase app indexing, developers, development guidelines, development team, programming

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