What is the `Authorization` part of the http post request of Google's Firebase Downstream message?

Question

I want to try to send a message using google\'s FCM messaging service and as the document says, the http request should be something like this:

Answer 1

According to About Firebase Cloud Messaging Server documentation:

Authentication

To send a message, the app server issues a POST request. For example:

https://fcm.googleapis.com/fcm/send

A message request consists of two parts: the HTTP header and the HTTP body.

The HTTP header must contain the following headers:

• Authorization: key=YOUR_SERVER_KEY

  Make sure this is the server key, whose value is available in your Firebase project console under Project Settings > Cloud Messaging. Client keys or any other keys are rejected by FCM.

• Content-Type: application/json for JSON; application/x-www-form-urlencoded;charset=UTF-8 for plain text.

  If Content-Type is omitted, the format is assumed to be plain text.

Hope it helps!

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UPDATE (2016/11/16)

Perhaps you should consider using the FCM token instead of the server keys as the note inside the following screenshot

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UPDATE (2016/12/08)

Firebase has upgraded the server keys to a new version and recommended that you upgrade to the newest version. Please see the screenshot below: