Polymarket + Kalshi Arbitrage Finder
Pricing
from $0.05 / actor start
Polymarket + Kalshi Arbitrage Finder
Scans both Polymarket and Kalshi for matching binary prediction markets and identifies price discrepancies where buying YES on one platform and NO on the other guarantees a risk-free profit. Returns ranked arb opportunities with trade instructions, spread, and return %.
Pricing
from $0.05 / actor start
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0.0
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Developer
Max Galli
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2 days ago
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Scans both Polymarket and Kalshi simultaneously, matches binary prediction markets on the same topic, and surfaces price discrepancies where you can lock in a risk-free profit by buying YES on one platform and NO on the other.
How the arbitrage works
Both platforms resolve the same way: YES pays $1.00/share, NO pays $0.00/share (or vice versa). If Polymarket prices a market at YES = $0.55 and Kalshi prices the same market at YES = $0.68:
| Action | Cost | Payout if YES | Payout if NO |
|---|---|---|---|
| Buy YES on Polymarket | $0.55 | +$1.00 | $0.00 |
| Buy NO on Kalshi | $0.32 | $0.00 | +$1.00 |
| Total | $0.87 | $1.00 | $1.00 |
Guaranteed profit: $0.13 per share = 14.9% return regardless of outcome.
What you get per opportunity
| Field | Description |
|---|---|
spread | YES price difference between platforms (0–1 scale) |
return_pct | Estimated profit % per dollar risked |
direction | Which platform to buy YES on, which to buy NO on |
buy_yes_url | Direct link to the YES side market |
buy_no_url | Direct link to the NO side market |
poly_yes_price | Polymarket YES price |
kalshi_yes_price | Kalshi YES price |
cost_per_unit | Total cost to capture $1 payout |
profit_per_unit | Guaranteed profit per $1 payout captured |
similarity_score | How closely the market questions matched (0–1) |
poly_end_date | Polymarket market close date |
kalshi_end_date | Kalshi market close date |
Input options
| Parameter | Default | Description |
|---|---|---|
minSpread | 0.02 | Minimum price difference to flag (e.g. 0.05 = 5 cents) |
minReturnPct | 0.5 | Minimum profit % to include |
minSimilarity | 0.25 | Keyword match strictness (higher = fewer, more accurate matches) |
minLiquidity | 0 | Filter out illiquid markets |
minVolume24h | 0 | Filter by 24h trading volume |
maxResults | 500 | Cap on results, sorted by return % |
Important notes
- Not financial advice. Real arb requires both trades to fill simultaneously. Slippage, transaction fees, and timing can reduce or eliminate the profit.
- Markets are matched by keyword similarity — always verify the two markets resolve on the same underlying event before trading.
- Kalshi operates in the US and is CFTC-regulated. Polymarket is accessible to non-US users only.
- Results are sorted by
return_pctdescending — highest-return opportunities first. - A
similarity_scorebelow 0.4 means the match is looser — verify manually before trading.
Example output
