Dashboard
Live spreads
Every open Kalshi, Polymarket and Polymarket US event, priced against the live order book after fees.
Right now
What the scanner sees at this moment, after every platform’s fees.
Profit & loss
Scanner coverage
Every open Kalshi, Polymarket and Polymarket US event, checked in rolling sweeps. Spreads already in the feed are re-priced about once a minute.
What makes this list
A short list is the point. This looks for arbitrage and nothing else: no model, no fair-value estimate, no pick. Four things have to be true before a spread reaches this table.
- The structure is verified, not assumed. Exactly one listed outcome must win: a Polymarket winner-take-all event, Kalshi brackets covering every result, two nested brackets on the same number, or a Polymarket US 3-way result or full-league championship. Events where an unlisted result could win are skipped even when the prices look free.
- The price is the book, at the size resting in it. Every leg is priced at the live best ask and the quantity actually offered there, then each platform’s own published fee formula is taken off. A spread that clears before fees and not after never reaches this table.
- What is listed can be placed from here. One tap sends every Kalshi and Polymarket US leg as a fill-or-kill limit order, up to 40 legs, thinnest book first, signed in this browser with keys that never reach our servers. Nothing is sent until you confirm the ticket.
- It is honest about what it is not. This is not the fastest scanner and does not claim to be: the feed re-prices about once a minute. The spreads that survive here are the ones faster tools skip, on quieter venues, at sizes not worth a bot’s time, or with money tied up for weeks.
Opportunities
Bundles that pay a fixed amount whichever outcome wins, priced at the best ask and the size resting there, after each platform’s fees.
| Event | Cost | Pays | Net | Return | Size | Profit at size | Closes |
|---|
Prices can change or disappear before you act, and every leg is a separate order; if one doesn’t fill you’re holding the others unhedged. Capital stays tied up until the event resolves. Fees shown use Kalshi’s published fee schedule, each Polymarket market’s own fee settings and Polymarket US’s published fee formula; your actual fills may differ. ArbTrader never trades on its own. Not financial advice.
Trade Checker
Check a spread you found somewhere else.
Paste a Kalshi, Polymarket or Polymarket US event and it goes through exactly the checks the scanner runs: does one listed outcome have to win, what is actually resting at those prices, and does it still clear after each platform’s fees. Most of the value is in the refusals, so it will tell you plainly when there is no trade and why.
Kalshi ↔ Polymarket pairs you’ve confirmed
Two platforms can list the same question with different wording, different criteria or a different deadline. ArbTrader won’t guess: search for a market on each side, read both sets of rules, and confirm the pair yourself. Confirmed pairs are priced in your feed as Kalshi YES + Polymarket NO (and the reverse) with both platforms’ fees taken out.
Kalshi
Polymarket
Alerts
Get a message when a spread clears your thresholds. Alerts are sent at most once per spread every six hours, and at most 20 messages an hour.
Kalshi
Your private key is imported into this browser’s key store so that page code can sign with it but can’t read it back out. Requests are signed here and passed through arbtrader.co, because Kalshi’s API doesn’t accept calls from web pages, the key itself never leaves this browser.
Polymarket
Polymarket positions and trades are public, so your P&L needs only your wallet address, no key, nothing to sign. Polymarket.com blocks orders from other websites, so its legs are always placed by you there. For Polymarket US order tickets, connect a Polymarket US key below.
Polymarket US
For one-tap tickets on Polymarket US spreads (Max). Polymarket US keys are Ed25519: the secret is imported into this browser’s key store so page code can sign with it but can’t read it back out. Requests are signed here and passed through arbtrader.co, the secret itself never leaves this browser.
Order log
Every ticket this browser has sent. Kept here only; your exchange account is the record that counts.
Anyone who can use this browser profile can use a connected key. Use a key with only the permissions you need, disconnect when you’re done on a shared computer, and remember that clearing this browser’s site data removes the key from here; revoke it on Kalshi or Polymarket US if you think it’s been exposed.
Where you can trade
What we could establish about each US state, as of the date shown on each entry. This is a starting point for your own checking, not legal advice; rules here change often, and each platform’s own terms decide who may use it.