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GET
Price spreads
Cross-venue price spreads for paired BTC windows (Kalshi ↔ Polymarket). Returns a JSON array sorted by absolute diff descending. Unlike /arbitrage/current, spreads compare the same outcome side across venues (e.g. Kalshi YES ask vs Polymarket YES ask). This is not risk-free arbitrage. For each paired window, the API emits up to two rows: one for YES, one for NO. diff is side1_price − side2_price where side1 is always Kalshi and side2 is Polymarket.

Request

Query parameters

minutes
integer
default:"10000"
Snapshot lookback window in minutes (maps to max staleness).
interval_code
string
5m, 15m, 1h, 24h, or 1w.
limit
integer
default:"50"
Max spread rows returned (1–100).

Response

side
string
YES or NO.
side1
string
Always Kalshi.
side2
string
Always Polymarket.
side1_price
number
Kalshi ask for the side.
side2_price
number
Polymarket ask for the side.
diff
number
side1_price − side2_price.

Examples

15-minute spreads