Hi all. I've been using Polymarket and Kalshi for a while and recently got really into the idea of building something similar myself. The concept makes total sense to me but once I start digging into the "how" I hit a wall.

Like — do you even need to build everything from scratch or can you use existing protocols? How do platforms actually decide who wins a market? What stops people from manipulating thin markets?

Also curious about the business side — how do these platforms even make money if fees are so low?