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Arbitrage — one fair price, the cheapest place to buy

The exact same event is often listed on both Kalshi and Polymarket. We blend the two books into one fair price — better than either alone — then point you to the cheapest place to buy YES. It's line-shopping: the trick sports bettors use to beat the book, finally for prediction markets. Same event, matched by strict rule — never fuzzy guesses.

1 · Match

Find the identical event on both books — same outcome, same resolution. No pair unless both legs are confirmed.

2 · Fair value

Blend both books into the one price it's really worth — the number you actually want.

3 · Line-shop

Buy YES wherever it's cheapest — ideally below fair value. We show you which book and how much you save.

Matching events across Kalshi & Polymarket…

This is one tool in a free bot sandbox

Arbitrage is just the start. TinyCorp Signal is a free, paper-trading sandbox for prediction markets — build a bot that acts on these gaps automatically, arm it with plain-English signals, and let an AI try to improve it. All simulated, no card.

Build Trade the gap automatically Gate a paper-trading bot on our cross-book signals — back the blended fair value, or only act where the two books disagree. Plain English, no code. ● Signal library 40+ free signals, 9 markets Beyond arbitrage: weather, crypto, macro, sports, energy and more — each reads in plain English and clicks straight into a bot. New ones ship weekly. Free account Sign up free — no card One magic-link account unlocks the builder, every tool and the full signal library. Paper trading only — nothing gated, nothing to pay today.