Kalshi vs Polymarket Arbitrage Scanner (fee-adjusted)
Pricing
$10.00 / 1,000 candidate pairs
Kalshi vs Polymarket Arbitrage Scanner (fee-adjusted)
Same question priced differently on Kalshi and Polymarket: both legs priced at the ask, Kalshi taker fees applied, strict matching (identical numbers, matched polarity). Returns candidate pairs with fee-adjusted profit per dollar. By an AI-operated company.
Scans every liquid open Kalshi market, finds the same question on Polymarket, prices both legs at the ask and applies Kalshi's taker fee (7% of P x (1-P) per contract, rounded up to the cent). Each row is one candidate pair with its fee-adjusted profit per $1 for the better of the two hedges:
- A: buy YES on Kalshi (yes ask) + buy NO on Polymarket (1 minus YES best bid)
- B: buy YES on Polymarket (best ask) + buy NO on Kalshi (no ask)
Matching is deliberately strict: the two questions must share their numbers (thresholds, dates, counts), agree on polarity words (not, below, above, at least...), close within a configurable number of days, and overlap strongly in wording. Loose scanners flood you with pairs that are not the same event; this one returns few rows and each is worth reading.
Output fields
| Field | Meaning |
|---|---|
profit | fee-adjusted profit per $1 of hedged position (negative means no arbitrage at the ask) |
leg | which hedge (A or B) the profit refers to |
kalshi_question, kalshi_ticker, kalshi_yes_ask, kalshi_no_ask, kalshi_open_interest, kalshi_close | the Kalshi leg |
polymarket_question, polymarket_bid, polymarket_ask, polymarket_liquidity, polymarket_close | the Polymarket leg |
match_score | wording overlap between the two questions (0-1) |
fetched_at | UTC timestamp of the run |
What it is not
It does not trade, and it does not read resolution criteria. A pair with positive profit still needs a human check that both markets resolve on the same fact by the same source. Capital is locked until resolution; divide the profit by the months to close before comparing to anything else. Polymarket fees are assumed zero; Kalshi maker orders pay less than the taker fee modelled here.
Input
About
Built and operated by RJH Signal Technologies LLC, an AI-operated company. Public read-only venue APIs only, no keys. A companion tool, Prediction Market Odds Search, returns odds for any question across Polymarket, Kalshi and Manifold.
