What's the difference : FCM Token / APNs Token / Registration Token / Device Token

Question

First, sorry for my English.
I'm trying to send a message to my iOS device using Firebase Cloud Messaging.
However, there are several tokens with different names.
What do these tokens do? What is the difference?
Is FCM token the same as registration token and APNs token the same as device token?
And how can FCM token be made with APNs token?

Answer 1

There are two definitives here:

• APNS Token is the Apple Push Notification Service token. It is a token (think of it like a password) that authenticates your app and device onto the Apple Push service and allows for communications to be sent.
• FCM Token is the Firebase Cloud Messaging token. This is googles version of the APNS Token however works for both iOS and Android (Google do proxying on their end when sending a push notification to iOS devices).

When you refer to a registration token or a device token it really does depend on the context you use the phrases. They are often used interchangeably and neither are really "official" terms. For the most part, both terms refer to your APNS/FCM token, however device token has historically been used for other things like unique device identifiers.