In Firebase console under Project Settings/General beneath the Project ID field there is a Web API key :
Where is this used? I know that the Server key found under Project Settings/Cloud Messaging is used as Authorization key to make calls to the firebase console:
I have also noticed that in google-services.json ther is an "api_key" property that has a "current_key" value which is different from both keys that I have mentioned. What is that key?
From my answer here:
google-services.json
was originally used for before Firebase (Google Sign-in, Analytics, GCM), I'm guessing it would be between Google Sign-in and Analytics. As also mentioned by @DiegoGiorgini here:The api_key value in google-services.json is not used by FCM. (it is used by other Firebase libraries)
So it can be for a separate Google non-Firebase or Firebase service.
Web API Key - this one I haven't had a chance to use before. However, I've seen other posts wherein this specific API key is used often on Web apps related to Firebase (possibly also for Auth purposes?), but I'm not entirely sure.
Server Key - as per the docs:
A server key that authorizes your app server for access to Google services, including sending messages via Firebase Cloud Messaging.