PredictMirror

PredictMirror is a Polymarket paper trading simulator that lets you practice on every market without putting a single dollar at risk. The extension overlays a trading panel directly on any Polymarket event page, pulling live prices from the real order book so your simulated trades reflect exactly what you would have paid or received on the actual market.

Start with $1,000 in virtual capital, your own Polymarket paper account with no wallet or signup required. Place BUY and SELL trades on any outcome across sports, crypto, politics, culture, and esports markets. PredictMirror calculates fees and slippage using Polymarket's exact formula, so the numbers match what you would see on the real platform down to the cent.

WHAT MAKES IT ACCURATE

Most paper trading tools use simplified math that drifts from real platform numbers. PredictMirror is built on a Polymarket paper trading engine that walks the actual order book depth to account for slippage on thin markets, applies the correct fee rate per market category, and mirrors the same share-based input format Polymarket uses for sell orders. The result is a simulation you can actually trust when you decide to trade for real.

KEY FEATURES

- Live prices from Polymarket's real order book, updated as you trade