Sending Push via Postman using Firebase Messaging

The correct way to set up Authorization key at Header is

key=<API_ACCESS_KEY>

and not only

<API_ACCESS_KEY>

Silly mistake, but since this could be useful for someone for testing Firebase Messaging with Postman I'm leaving the question opened.

Open Postman, click on Enter request URL textbox, enter firebase url

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

Than change request type to POST. See below screenshot:

Now to click on Header and add two params Content-Type and Authorization.

Content-Type= application/json
Authorization=AIzaSyAEb3NhsfGw1ih5mn8cmrGUAXMp86waQ //FCM SERVER KEY

See below screenshot:

Now click on Body than select Row and add value as object like below

{ 
"to":"eB5papU2Xdc:APA91bFFvc3dXru1fN5JY8U19oHIpfGhPUx7Ll7v9vJYTsIGZ15mDwB2Wpep3flLK85IUqqs2WqJwjYHSDYX28oJ1wTP0R2TDc2ba_uVjUauDcp3pCNKr_0KlghOnS", 
 "notification" : {
 "body" : "New announcement assigned",
 "OrganizationId":"2",
 "content_available" : true,
 "priority" : "high",
 "subtitle":"Elementary School",
 "Title":"hello"
 },
 "data" : {
 "priority" : "high",
 "sound":"app_sound.wav",
 "content_available" : true,
 "bodyText" : "New Announcement assigned",
 "organization" :"Elementary school"
}
}

Now your Postman would look like this. Click Send button at top right.

Good luck!