GCM API key vs Sender ID

Question

I am confused about GCM Sender ID and API key. I\'m responsible for building 3rd party server that will send notifications to Android app.

Which one do I have to store o

Answer 1

I've kinda figured it out on my own:

1. API key is generated on console and is used by 3rd party server to authenticate/authorize with GCM.
2. Sender ID is used by Android app to register a physical device with GCM to be able to receive notifications from GCM from particular 3rd party server.
3. Registration ID is a result of registration of physical device to GCM with Sender ID.