How to fix core/duplicate-app] A Firebase App named "[DEFAULT]" already exists error

Introduction

In this article we will cover the fix for [core/duplicate-app] A Firebase App named "[DEFAULT]" already exists exception.

If you tried running your flutter app that's using a firebase product you might see this error if your GoogleService-Info.plist or google-services.json files are outdated.

[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: [core/duplicate-app] A Firebase App named "[DEFAULT]" already exists

Solution

To fix the core/duplicate-app] A Firebase App named "[DEFAULT]" already exists exception follow these two simple steps

1. Delete your google-services.json located at android/app/google-services.json if running on android or delete your GoogleService-Info.plist located at
   macos/Runner/GoogleService-Info.plist if running on MacOS or ios/Runner/GoogleService-Info.plist if running on IOS.

2. Install and Run the flutterFire CLI in the root of your flutter project directory.

If flutterFire CLI not already installed run

$ dart pub global activate flutterfire_cli

Next Run

$ flutterfire configure --project=<yourprojectID>

Follow the instructions in your terminal.

Your flutter project should now run successfully.

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Comments

[Chen Chou]

Thank you @curtlycritchlow this helps and make sense than all other solutions.

[Curtly Critchlow]

You're welcome @chenchou.

[ABDELHAK ME]

Very helpful ,thank you so much

[Curtly Critchlow]

You're welcome @abdelhak_mehda

[JoyEnergiser]

this fixed it the first time but I have been playing around with different environments switching between dev and uat and now this doesn't fix it anymore. Any suggestions ?

[JoyEnergiser]

I found the problem, I had used the same packagename in two different firebase accounts in two different projects

[Kamal Kishor Kumar]

Thanks, that was helpful