Prediction market arbitrage sounds straightforward: find the same event priced differently on Polymarket and Kalshi, buy both sides, collect a spread that's fixed regardless of the outcome. In practice, doing this manually is nearly impossible at any meaningful scale. Here's why automation is essential — and what a good Polymarket arbitrage agent actually does.
Manual arbitrage: the limitations
Manually monitoring arbitrage opportunities across thousands of prediction market contracts requires:
- Checking both Polymarket and Kalshi simultaneously for price divergences
- Matching events correctly across platforms (same event, different titles)
- Calculating edges after fees fast enough to act before the window closes
- Executing both legs near-simultaneously to avoid leg risk
Arbitrage windows on active markets can close quickly. A human checking manually every few minutes will miss many opportunities, and you can't watch thousands of markets at once.
What an arbitrage agent does
A proper Polymarket/Kalshi arbitrage agent does the following in a continuous loop:
- Event matching: Maps the same real-world event across both platforms despite different titles, contract structures, and resolution criteria.
- Price monitoring: Polls prices on both platforms continuously to detect divergences.
- Edge calculation: Computes the net edge after both platforms' fees to verify the opportunity is actually profitable.
- Dual-leg execution: Fires both orders near-simultaneously to minimise leg risk.
- Position management: Tracks open positions, monitors for fill confirmation, and triggers kill-switch logic if a leg fails to fill.
Arbitrage Agent: how it works
Arbitrage Agent uses AI-powered event matching to identify the same event across Polymarket and Kalshi — the hardest part of cross-platform arbitrage. It monitors thousands of active markets continuously, calculates net edges explicitly (including fees), and alerts you with a step-by-step guide when an opportunity meets the threshold (automated execution in final testing).
Key features: dry-run mode for safe testing, Kelly criterion sizing, configurable edge threshold, Telegram alerts, and a live dashboard showing all open positions and resolved P&L.
What to look for in an arbitrage agent
- Event matching accuracy: False matches (different events mistakenly identified as the same) will cause losses. The matching algorithm is the most important component.
- Execution speed: Fast alerting matters most while execution is manual — the agent should surface a matched pair with both legs specified the moment a threshold is crossed, not minutes later.
- Fee modelling: The agent must calculate net edge after fees, not gross edge.
- Leg risk management: Kill switch and retry logic for failed second-leg fills.
- Dry-run mode: Essential for verifying the agent's behaviour before committing real capital.
Join the Arbitrage Agent waitlist to get early access to an agent built specifically for Polymarket/Kalshi cross-platform arbitrage.
Related articles
- Polymarket Kalshi Arbitrage Agent: The Complete 2026 Guide
- How to Arbitrage Polymarket vs Kalshi
- How Much Can You Make with Prediction Market Arbitrage?
- Is Prediction Market Arbitrage Really Risk-Free?
Key terms: Dry Run (Paper Trading) · Cross-Market Arbitrage · Two-Leg Execution