Stop guessing on prediction markets.

An arbitrage scanner for prediction markets that runs on the web. Log in at arbtrader.co and your dashboard checks every open Kalshi, Polymarket and Polymarket US event, plus Novig’s and Gemini’s sports games (beta), for bundles that pay more than they cost after fees, and shows the legs, prices, size and links. Connect your accounts and it also draws your profit & loss, computed in your browser, from your own trade history. Quant adds alerts, Kalshi ↔ Polymarket pairs you confirm, and Kalshi and Polymarket US order tickets you confirm.

Yes. Join our Discord and the ArbTrader team helps you one to one: turning on alerts, connecting Kalshi or Polymarket US, reading a spread and placing your first one. Quant and Terminal members get 1-to-1 coaching; everyone on the free plan gets help in the server too. We teach you how to use ArbTrader; we don't tell you what to trade, and nothing we say is financial advice.

Yes. ArbTrader is built by a solo founder who uses it with his own money: he takes spreads it finds on his own live exchange accounts, the same way subscribers do. That isn’t a promise of profit. Prices can move before every leg fills, and the risks page covers what can go wrong.

Both run the same one-winner bundle scanner across every open Kalshi, Polymarket and Polymarket US event, plus Novig’s and Gemini’s sports games (beta). Base is free and shows you each spread on a delay of up to a minute, with its return and how long it has left, but not the legs, prices, sizes or links; you can watch the scanner work, you just can’t act on it. Quant ($45 a month, about $1.48 a day, including your first 7 days) unlocks all of that, plus your P&L, the AI Analyst and Whale Tracker, email and Discord alerts, Kalshi ↔ Polymarket pairs, and one-tap Kalshi and Polymarket US order tickets you confirm. Terminal ($149 a month) is everything in Quant plus auto-place, the fast lane, middles and a parlay builder; more on it below. International Polymarket legs are placed by you on every plan.

Terminal is ArbTrader for people who trade spreads often: everything in Quant on one fast screen, with a live tape of spreads and middles, an inspector for each one and keyboard shortcuts. It adds Auto-place, which places every spread that meets your rules (minimum return, dollars per spread, daily cap, how soon it must pay out) on your connected Kalshi and Polymarket US accounts while the Terminal is open, in Safe mode (about 1 second) or Instant mode (about 0.3 seconds, where more often one side fills alone and is sold back, usually for a small loss); the fast lane, which shows new spreads about a second after they’re listed (Quant sees them a few seconds later); middles, the same game’s total at different lines on Kalshi and Polymarket US; a parlay builder; resting orders (beta) on near misses; line-move alerts; a leg-risk guard and live profit; and priority 1-to-1 coaching. It costs $149 a month or $1,490 a year, and your first 7 days are billed at $4.90 a day. Try it first with sample data in the Terminal demo. Every spread is an edge, not a sure thing, and none of this is financial advice.

Only when you tell it to. On Base, no; it reports opportunities and you place every trade by hand. On Quant it links you to each leg, and it can also send Kalshi and Polymarket US orders, but only when you open the ticket for a specific opportunity, set the size, let it re-check the live prices, and confirm; each leg goes out as a fill-or-kill limit order at the price you approved. Two exceptions are ones you switch on yourself. On Terminal, Auto-place places every spread that meets the rules you set (minimum return, dollars per spread, daily cap) on your connected accounts while your dashboard is open, after you say yes once to real orders; you can turn it off any time. And Auto-sell, which you can arm on a position you already hold so it sells that position once you’d be ahead by the amount you set. It sells while your dashboard is open; when it’s closed, we email you the moment the target is hit so you can sell with one tap. It never buys, fires once and then turns itself off. Separately, Quant pings you when a spread you hold can be closed early for most of its profit; that alert never sells anything. International Polymarket blocks orders placed from other websites, so those legs are always yours to place.

You do. Your Kalshi private key (and, for Quant tickets, your Polymarket US secret) is imported into your browser’s own key store as a non-extractable key: the dashboard can ask the browser to sign a request with it, but neither the page nor we can read the key back out, and it is never uploaded. Each request is signed in your browser and passed through arbtrader.co only because the exchanges’ APIs don’t accept calls from web pages; we forward the signed request and the exchange’s answer, and never see the key. International Polymarket needs only your public wallet address. We never hold your funds on any platform.

Just an ArbTrader account. The live feed works the moment you log in; it uses public market data, not your accounts. A Kalshi API key and your Polymarket wallet address are optional and only power your P&L; on Quant, a Kalshi or Polymarket US key with trading permission powers order tickets. Discord alerts need a webhook URL from a server you control. You add all of these on the Connections tab of your dashboard, and you can remove them with one click. Want to look around first? Try the live demo.

The scanner finds a spread about 0.3 seconds after the prices move on the markets it follows live (Polymarket’s order books, plus Kalshi–Polymarket game pairs, where Kalshi’s side is re-read every 2 seconds). Quant dashboards update the moment a spread lands, and alerts go out at the same time. Other listed spreads are re-priced about every 15 seconds, and it sweeps all 40,000+ open events in rolling passes (a full pass of Polymarket’s ~22,000 takes several minutes). It can still lag the market: dedicated bots react in milliseconds. Order tickets re-read the live order book the moment before you confirm, and refuse the ticket if the price moved or the size isn't there. Real spreads are rare and close fast; a human confirmation is part of every order by design, and nothing guarantees a fill at the price you saw.

No. ArbTrader is software that surfaces pricing information across platforms and, on Quant, sends orders you've reviewed and confirmed. Whether to trade, and how much, is always your decision and your risk.

Yes, anytime, including during the trial; you won't be charged unless you're still subscribed when it ends. Pause, switch to yearly or cancel from your account page, or drop back to Base for free. It's a monthly subscription with no lock-in.