We'll soon start assigning user IDs with the pattern: XXX000 (current pattern: XX0000).
While this doesn't change the Kite login mechanism in any way, new users will have user IDs with three (3) alphabetic characters instead of the current two (2).
If you validate the user ID on your end to allow Kite login for multiple users on your platform, please accommodate this update.
All existing users will retain their user IDs in the current format (XX0000).
So basically zerodha is going to cross 26*25*10*9*8*7 = 3,276,000 users, which is 3.276 million but your website says you have 5 million user base. Anyways kudos for the milestone, hope it crosses 11.232 million soon.
where C stands for combination operation