Lots of requests to mongo?

Question

MongoDB

I have a node js project. When buying from a person, the balance is removed after checking certain conditions of the purchase. If you make requests very quickly, then you can, having a product for 100 rubles and on a balance of 100 rubles, buy it 2 times, for example, and drive the balance into a minus. how to deal with it? I read about the atomicity of operations in mongo, but I didn’t understand it well

Answer 1

Just don't use mongodb for this. mongo is written to store non-valuable data

Answer 2

How to get around the lack of transactions in MongoDB?