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Polymarket vs Kalshi Yes-Price Spread Lookup
x402
Polymarket vs Kalshi Yes-Price Spread Lookup is a paid API for AI agents from aizamon.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-20).
Returns the yes-price spread between Polymarket and Kalshi for a given prediction market topic, identifying the cheaper venue and providing deep links.
Price / call$0.001
Success—
StatusUnknown
How this service works
Exact Polymarket and Kalshi yes prices for one topic. Pass ?q= as keywords, or omit q for the widest live gap. Returns gapCents, the cheaper venue, the Kalshi ticker and URL, and the Polymarket slug and URL. This is the mid-price gap. The cents left after you buy the ask and sell the bid are the net read. $0.001 USDC. The hour pass covers it.
Output
Returns the exact yes prices on both Polymarket and Kalshi, the gap in cents between them, which venue is cheaper, and direct deep links to both market pages — all in a single composable read.
Example use cases
Arbitrage opportunity scanner
“Check the yes-price spread between Polymarket and Kalshi for the Fed rate cut market — I want to know which venue is cheaper, the exact prices, and links so I can act fast.”
Pre-trade venue selection
“Before I buy yes shares on the Trump 2024 presidential win market, can you tell me whether Polymarket or Kalshi has the lower yes price right now and by how many cents?”
Top gap discovery
“I don't have a specific market in mind — just show me whichever Polymarket vs Kalshi market has the biggest yes-price spread right now so I can see where the best arbitrage opportunity is.”
Technical details
Endpoint
GEThttps://aizamon.com/x402/v1/spread?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need a quick, cheap ($0.01) single-market yes-price comparison between Polymarket and Kalshi, especially for spot-checking a specific topic or finding the top gap opportunity without paying for a bulk arbitrage pack. Prefer the $0.89 pack endpoint if you need the top 5 gaps with fee-adjusted net edge data instead.
Side effects
- No matching market found for the given topic query — returns empty or null result
- Topic query too ambiguous to resolve to a unique market on both venues
- One or both venues may not have a listed market for the query, resulting in partial data
- Network or upstream API errors from Polymarket or Kalshi data sources
- Payment failure or x402 authorization issue preventing the call from completing
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"sku": "SKU_AG_SPREAD_01",
"result": {
"spread": {
"query": "openai ipo",
"topic": "Will Anthropic or OpenAI IPO first?",
"kalshi": {
"url": "https://kalshi.com/…",
"yes": 0.42,
"ticker": "…"
},
"gapCents": 8,
"cheaperOn": "kalshi",
"polymarket": {
"url": "https://polymarket.com/…",
"yes": 0.5,
"slug": "…"
}
},
"product": "Cross-venue Spread — exact tick"
},
"protocol": "x402"
}
}Tags
x402
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