Building fair real-time odds for CS2 stream predictions

The author describes building elo.market, a live prediction system for CS2 streams where viewers bet virtual elo on in-game events. The core challenge was designing dynamic odds that feel fair—naive pool-based calculations allowed whales to exploit the market. The key fix was decoupling bet size from crowd consensus by using a fixed vote unit for voter influence, preventing large bettors from dominating both the amount and headcount signals.