These four keys are required to set up and initialize Firebase settings. You can find what and where by following these steps.

1. apiKey - Inside you downloaded "google-service.json" search for

   "api_key": [{

   "current_key": "AIzaSyCVXXXXXX_T8BXDVs8Sehg_LmikE"

   }]

2. appId - Go to firebase console -> project settings -> search for appId and copy it

3. messagingSenderId - In your downloaded "google-service.json" file, search for project_number (this is your messagingSenderId)

4. projectId - Same as appId, you can get this from firebase console's project settings

I hope these will help in future implementations. As this question asked long ago 😊

Anyway happy coding !🤘🏻