For those new to the concept, an arbitrage lock in prediction markets occurs when you can buy a 'YES' contract on one platform and a 'NO' contract for the same event on another platform, with the combined cost being less than $1. This strategy guarantees a profit regardless of the event's outcome, as one of your contracts will always pay out $1.
As of July 27, 2026, our StartupHub.ai engine has surfaced five such opportunities across Polymarket, Kalshi/Robinhood, and PredictIt. These spreads can close rapidly due to market dynamics, and potential profits should always be considered alongside platform fees, KYC requirements, and withdrawal limits.
Track these live, or poll the free API
The board above refreshes on its own, so this page stays current long after today. The full cross-venue feed lives on the arbitrage board, and every match is also a free JSON API and an MCP tool, so a trading agent can poll live Polymarket, Kalshi and PredictIt arbitrage opportunities and act on them.
curl https://www.startuphub.ai/api/v1/arbitrage?arbs_only=1Read the arbitrage API reference or open the live JSON endpoint.
Informational feed, not financial advice. Live arbitrages are often fleeting, and fees, gas, KYC and withdrawal limits eat into the spread. Verify each market’s resolution rules and costs before trading.