Start free. Upgrade when the edge pays for itself.
The scanner and analyzer are free forever. Pro adds the arbitrage feed, unlimited alerts, journal analytics and the in-page extension overlay.
Every cross-venue pair is machine-checked to confirm both sides settle on the same criteria. Nothing is labelled risk-free without that proof.
Arbitrage is priced off live ask prices with each venue's exact fee model — not midpoints that vanish when you try to trade them.
Opportunities are ranked by annualized return, never by who pays us. No sponsored rows mixed into live results.
- Full edge scanner, all venues
- Analyzer: fair value, EV, quarter-Kelly sizing
- Venue comparison with resolution check
- 3 watchlist alerts
- Arbitrage feed
- Everything in Free
- Arbitrage feed — real asks, exact fees, APY-ranked
- Unlimited watchlist alerts by email
- Smart Money whale feed
- Trade journal, P&L and accuracy analytics
- Chrome extension overlay on Kalshi & Polymarket
- REST access to edges, markets and status
- Python and JavaScript SDKs
- MCP server for Claude, Cursor and friends
- Free tier to build against before you pay
Pro is month-to-month through Stripe's billing portal — no phone call, no retention flow. Cancel and you keep access until the period you already paid for ends.
How we differ from other aggregators
Most tools in this space compete on how many venues they list. We compete on whether the number in front of you is one you can actually trade.
| Capability | MarketMaster | Typical aggregator |
|---|---|---|
| Machine-verified that both legs resolve identically The failure mode that turns an "arb" into a loss | Yes | Manual disclaimer |
| Arbitrage priced at live ask, not midpoint Midpoints overstate every opportunity | Yes | Varies |
| Exact per-venue fee model in the math Kalshi's curve differs by price; a flat estimate is wrong at the tails | Yes | Flat estimate |
| Ranked by annualized return A 3c lock tonight beats a 5c lock in 2027 | Yes | Raw spread |
| Ambiguous pairs withheld rather than shown We drop a group rather than print a number we cannot stand behind | Yes | Rarely |
| Sponsored placements inside the live feed | Never | Common |
| In-page overlay on the exchange itself | Chrome extension | Site only |
Data API
The same matched-market and edge data the product runs on, available as a documented REST API with official SDKs and an MCP server. Start on the free key and upgrade only when your volume needs it.
Questions, answered
Does Pro guarantee I'll make money?+
No, and treat any tool that says otherwise with suspicion. MarketMaster is an analytics product. It shows where two venues disagree, prices that gap honestly after fees, and tracks your results. Prediction markets carry a real risk of loss and nothing here is financial advice.
What does "resolution-checked" actually mean?+
Two markets can look identical and still settle differently — different sources, cutoff times or tie-breakers. Before we call a pair an arbitrage, an automated verifier compares both venues' resolution criteria and records a verdict. If it has not confirmed a match, the opportunity is still shown but is never labelled risk-free.
Is the free plan actually usable?+
Yes. The full scanner, the analyzer with fair value and quarter-Kelly sizing, and the venue comparison are all free with no time limit. Pro exists for people who want the arbitrage feed, unlimited alerts and the journal, not as a way to make the free tier useless.
Do you need my exchange login?+
Never. The journal reads an optional read-only Kalshi API key or your public Polymarket wallet address, purely to display your own positions. MarketMaster cannot place trades or move funds, by design.
How do I cancel?+
Dashboard, then Manage billing, which opens Stripe's own portal. Cancel there and access continues until the end of the period you have already paid for. There is no retention flow to sit through.
Why only Kalshi and Polymarket?+
Because they are the two real-money venues where cross-listing is common enough for the comparison to mean something. Adding thin venues would inflate our market count and degrade match quality — the opposite of the trade-off we want to make.
Prices in USD. Billing handled by Stripe; we never see your card details.
MarketMaster is an information tool, not a broker, and does not provide financial advice.