I am looking to build a Realtime online Bidding system or an Auction portal. I have working knowledge of Spring Boot, MongoDB and basic UI http://bedcollege.herokuapp.com/

What I understand is that to build this it requires auto update of prices in the real-time across all the bidders when any other bidder submits any bid. I want to know what kind of technology is there to support it and any recommendation to couple with Spring Boot?