I have been looking for an answer to this question for months believe it or not, but have not found anything definitive.
Many finance based apps (including free apps) allow users to set simple ‘price alerts’ for a particular market (eg. stocks, bitcoin, etc). When price crosses that threshold, the user receives their custom APNS alert/notification. How are these alerts generated- eg. a backend server constantly monitoring price and iterating possibly thousands of individual user devices to send custom individual alerts (this seems like quite a heavy process to run 24/7)? Or is there something simpler, that I am missing?
Any advice or resources as to where I could find help for this would be greatly appreciated.