Web server best practices

I need a suggestion on a design decision. I am creating a ecommmerce app and have a lot of items (>10000) to show in my app. Now here are the 2 options I have 1) Get all the items information from the server and save in local db and synchronize the information every time (let say 15 min) 2) Get the information every time from the web server (through rest api).

There are pros and cons of both the methods. Using local db I can get fast results and less server bandwidth but will have to handle synchronization With second approach, I will have a lot of server request to and free and load on server.

I would also like to know how does other apps like amazon and flipkart handle this. Do they save in local db or request server every time.