Scans Polymarket and Kalshi every 5 minutes for identical events. Computes real net edge after fees and slippage. Only shows opportunities above 1% — because anything smaller isn't worth the execution risk.
Pulls top-volume Polymarket markets (Gamma API) and Kalshi events (with nested markets). Matches by Jaccard similarity on the question title — requires a shared entity (Trump, Bitcoin, Iran) plus an adjacent word pair.
For each matched pair, pulls the best bid + best ask from both venues in parallel. Uses midpoint if the spread is under 2¢; uses ask if wider.
For each matched event, checks both directions: Buy YES on Poly + NO on Kalshi, and vice versa. Subtracts: 2% Polymarket fee, Kalshi per-trade fee, and 0.5% slippage buffer.
Only shows arbs with net edge > 1% AND combined liquidity > $25K. Smaller or thinner opportunities are excluded to avoid wasting your attention.
All markets re-scanned every 5 minutes. Spreads move fast — a 2% arb found at 10:00 may be gone by 10:05.
Each arb shows: market title, both venue prices, net edge %, recommended position sizing, and deep links to both exchanges. One click per venue to execute.
Cross-platform pricing differentials are theoretically lockable. In practice, three things can hurt you — and they are the reason most retail attempts to capture them underperform:
You see a 2% arb. You go to buy. By the time your order fills, the spread is 0.8%. This happens most on thin markets. Our filter excludes markets with under $25K combined liquidity for this reason.
Polymarket uses UMA oracle (community arbitration). Kalshi uses internal review. On rare occasions, they resolve equivalent-looking markets differently — turning a theoretical lockable spread into a 100% loss. We mitigate by only matching identically-worded markets.
Your money is tied up on both venues until both resolve. A 2% spread on a 6-month market is only a 4% annualized return. Always evaluate spread per unit of time, not just per trade.
This is not financial advice. Trading prediction markets involves risk of loss. Read our full disclaimer.
Polymarket arbitrage refers to a pricing discrepancy that arises when the same real-world event is priced differently on Polymarket versus another venue — usually Kalshi. PolySharks identifies and displays these spreads for informational analysis. Whether and how to act on the data is entirely up to the user, and is subject to fees, slippage, capital lockup, and resolution-divergence risk.
We pull top-volume Polymarket markets via the Gamma API and top Kalshi events via /events?with_nested_markets. Markets are matched using bigram + entity-keyword similarity (Jaccard ≥ 0.35 with a stopword filter). Live bid/ask from each venue is pulled, fees subtracted, and only edges >1% net are surfaced. Refreshes every 5 minutes.
On matched markets with $100K+ combined liquidity, gross spreads of 2–7¢ are common. After 2% Polymarket settlement fees and Kalshi per-trade fees, net edge is usually 0.5–3%. Our engine only shows arbs above 1% net edge — smaller ones aren't worth the execution risk.
No. Cross-platform pricing differentials are theoretically lockable, but in practice three real risks remain: (1) slippage during execution, especially on thin markets; (2) resolution disputes — both venues have occasionally resolved “equivalent” markets in different ways; (3) capital lockup — your funds are tied up until both markets resolve. Our matcher only surfaces identically-worded markets to minimize (2). PolySharks displays data for informational analysis only and makes no guarantees about returns.
Yes, but only on the deepest markets. Professional arb desks take the $50K+ opportunities. Retail-sized arbs ($500–$5,000) that slip through are what most PolySharks Pro users target. You need accounts on both Polymarket and Kalshi, plus reasonably fast execution.
Free tier shows the top 3 live arbs. Pro ($19.99/mo) shows all live arbs plus historical spread analysis.
PolySharks.ai is a market-intelligence and analytics platform operated by 8eight8 LLC. The site is provided for informational and educational purposes only — it is not financial, legal, tax, or gambling advice. Past whale performance and historical data carry no guarantee of future outcomes. Trading prediction markets involves substantial risk of loss, including 100% of principal. Users are solely responsible for compliance with the laws of their local jurisdiction — prediction-market access is restricted or prohibited in some US states and countries; verify legality before depositing or trading on Polymarket or Kalshi. PolySharks does not custody funds and is not affiliated with Polymarket Inc. or Kalshi Inc. 18+ only (21+ in some jurisdictions).