I want to make a price alert app but... Need advice

Hey,​I want to make a basic bitcoin price alert app(it'll be a web app). Just like the all other crypto price alert apps on phones.​- People will choose the prices for getting alerts for- When the price hit there app will send them browser notifications​There are numerous examples for such systems, like:- https://coinwink.com/- https://coinmarketalert.com/- https://coindera.com/- https://cryptocurrencyalerting.com​and so on.But, the thing I don't know is how to design such a system. Imagine I have 1000 users. What should I do? Should I save everyone's alert price points to a database and check from there, for example, every 5 seconds if the should get a notification or not? But such a system doesn't seem like a wise way of doing this task. If I have 100k users instead and every user have 10 saved alerts that makes 1m entry to check, how can I query that database every 5 seconds? Isn't this a heavy work for a database? And another thing is I may want to decrease the checking time to 1 second instead of 5, now thing are getting more harder​​I need your advice about it, anything appreciated. Thank you.​Lastly, I'm a CSE student and I do not have so much idea of how real-world problems are solved, so that question may be absurd for you. Just want to learn how I can accomplish that problem

Submitted May 29, 2019 at 08:35PM by ofaruk