Where two prediction markets disagree about the same future.
A scanner for price disagreements between Polymarket, Kalshi and Manifold: it matches markets about the same event and prices the gap two ways — true arbitrage, and plain divergence with EV and Kelly sizing.
It pulls every liquid binary market from the three venues, figures out which ones are about the same real-world event, and prices the gaps. True arbitrage is when buying YES on one venue and NO on the other costs less than the $1 it pays back. Divergence is when the venues just disagree and one side is cheap if you trust the other venue’s odds.
A warning is built into the report and repeated constantly: matching titles is not the same as matching markets. Two venues can word a question identically and still resolve it differently. discrepa finds candidates and does the arithmetic; reading both rule sets is your job. Quotes are top-of-book without depth guarantees, Kalshi taker fees are modelled, and Manifold is play money — so it only ever appears as a signal, never as a leg to buy.
- Fetches every liquid binary market from three venues — public APIs, no keys
- Event matching across venues with different wording
- True arbitrage: YES + NO across venues for under $1
- Divergence pricing with EV and Kelly sizing
- Fees modelled; play-money venues signal-only
- HTML report plus an append-only edges.jsonl so flagged edges can be tracked to resolution