What is the difference between the two different API keys provided from FCM

Question

while creating an FCM project I noticed two different API-keys provided as follows;

1- in the google-servies.json file

"api_key": [
        {
          "current_key": "the key"
        }
      ],

2- and another one called Web API Key in the app settings on firebase console

What is the difference between both of them and the usage?

Answer 1

Web Api key is used to connect your server with google cloud to send message to your apps. For example :

Content-Type:application/json
Authorization:key=AIzaSyZ-1u...0GBYzPu7Udno5aA

{
  "to" : "bk3RNwTe3H0:CI2k_HHwgIpoDKCIZvvDMExUdFQ3P1...",
  "data" : {
    ...
  },
}

https://developers.google.com/cloud-messaging/http