> ## Documentation Index
> Fetch the complete documentation index at: https://docs.probsights.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Arbitrage overview

> Cross-venue arbitrage opportunities and price spreads.

ProbSights pairs Kalshi and Polymarket BTC markets with a canonical fingerprint
matcher, then exposes fee-adjusted arbitrage and same-side price spreads.

| Endpoint                                                  | Use for                                                                |
| --------------------------------------------------------- | ---------------------------------------------------------------------- |
| [Cross-venue arbitrage](/api-reference/arbitrage-current) | Risk-adjusted YES/NO cross buys where net edge is positive after fees. |
| [Price spreads](/api-reference/arbitrage-difference)      | Where venues disagree on the same outcome side (not risk-free arb).    |

## How pairs are built

Pairs are rebuilt on a short refresh cycle using exact outcome fingerprints (not
fuzzy title matching):

| Matcher              | `match_method`   | What it matches                               |
| -------------------- | ---------------- | --------------------------------------------- |
| BTC Up/Down interval | `btc_interval`   | Same interval + window slot                   |
| BTC strike / bracket | `bracket_strike` | Exact strike cents + settlement day + horizon |

Each pair includes `fingerprint`, `confidence` (clock alignment), and
`settlement_fidelity` (`identical` or `window_skew`).