LIVEFull-depth Polymarket Up or Down order books for Bitcoin, Ethereum, Solana, XRP, BNB and Dogecoin, with the Chainlink price each market settles on.
Two outcome tokens that move together (e.g. two candidates in one primary, or BTC-above-X vs ETH-above-Y) usually trade at a stable price relationship. A Kalman filter is a running estimator that keeps re-fitting that relationship as new ticks arrive, so its ratio adapts faster than a fixed formula. You trade the spread between the two tokens whenever it drifts too far from the filter's current estimate, betting it snaps back. The edge: the on-chain order book is slow to reflect the true co-movement that the recursive estimate captures first.
Markets on Polymarket where kalman-filter pairs on cointegrated outcome tokens is the natural play: