GCM - Max length for Registration ID

Update: GCM is deprecated, use FCM

What is the maximum length for a Registration ID issued by GCM servers? GCM documentation do not provide this info. Googling for this reveals that Registration ID is not fixed length in nature and can be up to 4K (4096 bytes) in length. But these are not official answers from Google. I am currently receiving Registration IDs which are 162 characters long. Can anybody help?

Solution 1:

On android-gcm forum a google's developer confirms it's 4k

Solution 2:

I am interested in know about this also. My reg id size is 183 chars. I suspect it won't be longer than 512 chars though, let alone 4K. Imagine sending bulk notification, a 4K reg id x 1000 = 4MB message size!

In the end, I just use the 'text' type in my MySQL table to store the registration id. So even if google send me a 1K, 2K, or 4K (very unlikely) reg id, I will be able to handle it.

Update: I have come across a new reg id size: 205.