Guides
What we learned building this
Mostly by getting it wrong first. Three things that decide whether a price difference between two venues is an edge or an expensive illusion.
Fundamentals3 min read
What cross-venue arbitrage actually is in prediction markets
Buying both sides of the same question on two venues for less than a dollar, and the three things that usually eat the difference.
Read itCosts1 min readHow Kalshi and Polymarket US fees actually work
Both venues charge more than the spread suggests, and neither charges a flat percentage. What the formulas look like and where they bite.
Read itRisk2 min readWhen two markets that look identical are not the same contract
Resolution sources, close times and the specific ways two venues can ask the same question and answer it differently.
Read itSee which side actually pays more
ArbScout matches the same question across Kalshi, Polymarket US, Polymarket and Novig, walks both order books to your size, and subtracts the fees each venue really charges.