Cross-Line Sports Arbitrage

How It Works The bot scans Polymarket sports markets for cross-line arbitrage opportunities — situations where the combined implied probability of mutually exclusive outcomes (e.g., Team A wins + Team B wins in a two-outcome market) sums to less than 100%, or where correlated markets price the same underlying event differently. It uses the CLOB V2 API to detect these gaps and execute paired trades simultaneously.

Entry Conditions Entry is triggered when a price gap across lines exceeds a minimum profitability threshold (net of fees and slippage). Both legs of the arbitrage are executed as close to simultaneously as possible to lock in the spread. TypeScript implementation suggests reasonably fast execution.

Exit Conditions Arbitrage positions are held to resolution as the profit is locked in at entry (assuming both legs fill at target prices). No early exit is needed if the arbitrage is clean.

Verified Results No PnL data published. Zero stars and zero forks. The repo was created only 5 days before this report (2026-06-28), making it extremely early-stage with no track record.

Risks True risk-free arbitrage on Polymarket sports markets is rare and short-lived. Partial fills on one leg create naked directional exposure. Sports markets can have wide spreads that eliminate apparent arbitrage when execution costs are accounted for. Last-second line movements before resolution can create unexpected losses. The very recent creation date suggests the bot has minimal testing history.