Building a Polymarket Trading Bot with Historical Data
How to build an automated trading bot for Polymarket using historical order book data for strategy development.
Trading Bot Architecture
A prediction market trading bot has two phases: development (using historical data) and execution (live trading). PolyHistorical powers the development phase with historical order book snapshots you can replay and test against.
Development Pipeline
| Phase | Description | Data Source |
|---|---|---|
| Research | Identify patterns in order book behavior | PolyHistorical API |
| Strategy Coding | Implement entry/exit logic | Python / TypeScript |
| Backtesting | Replay historical snapshots | PolyHistorical API |
| Paper Trading | Run strategy on live data without real money | PolyHistorical + Polymarket |
| Live Execution | Execute real trades on Polymarket | Polymarket CLOB API |
Signal Generation with Order Book Data
The most effective prediction market signals come from order book analysis:
- Depth imbalance: When bid depth significantly exceeds ask depth (or vice versa), price movement often follows
- Spread compression: Narrowing spreads indicate growing consensus and potential breakout
- Liquidity shifts: Sudden removal of depth at key levels can signal informed trading
- Cross-market signals: Compare BTC Up/Down order books with ETH and SOL markets for correlation trades
Example: Depth Imbalance Signal
def calculate_imbalance(orderbook):
bid_depth = sum(float(l["size"]) for l in orderbook["bids"][:5])
ask_depth = sum(float(l["size"]) for l in orderbook["asks"][:5])
total = bid_depth + ask_depth
if total == 0:
return 0
return (bid_depth - ask_depth) / total # -1 to +1
Risk Management
- Never risk more than 2-5% of capital on a single market
- Set maximum position sizes based on historical liquidity analysis
- Monitor for regime changes — strategies that worked historically may break
- Always backtest with PolyHistorical data before deploying with real capital