50 Million Notifications, One Message ?
Sending a flash sale alert to every user sounds simple until you do the math on polling. This one explains it with a real example: the server load polling creates, and how FCM's pub/sub topic avoids sending millions of individual messages.
You'll learn why polling doesn't scale, why topics are the fix, and why the real risk shows up right after users tap the notification.
Would you have thought about the thundering herd part? Tell us in the comments ?
#SystemDesign #FCM #PushNotifications #TechInterview #Scalability #BackendEngineering #SoftwareEngineering #DistributedSystems #MobileEngineering #InterviewPrep