Both scan prediction markets for cross-venue arbitrage. The honest difference is scope and price: ArbBets is a wider, more expensive sports-and-prediction arbitrage suite starting at $59/month; MarketMaster is a focused Kalshi ↔ Polymarket edge terminal that is free to use and $12.99/month for the arbitrage feed.
Trade sports arbitrage or need Opinion coverage? ArbBets. Want an automated execution bot? ArbBets.
Trade Kalshi and Polymarket, want to see the scanner before paying anything, and care whether an "arb" survives fees and resolution differences? MarketMaster.
Prices and features taken from each product's own pricing page on 23 August 2026. Both change often — check before you buy.
| MarketMaster | ArbBets | |
|---|---|---|
| Cheapest way in | $0 — free forever, no card | $59/mo Basic · no free tier |
| Arbitrage feed | $12.99/mo Pro | $149/mo Pro |
| Top tier | $129/yr (Pro annual, 2 months free) | $299/mo Premium · $2,990/yr |
| Venues | Kalshi, Polymarket | Kalshi, Polymarket, Opinion |
| Sports arbitrage | Not offered | Yes — from Basic |
| Fair value & EV model | Yes — modelled fair value, EV edge, quarter-Kelly sizing | Yes — +EV finder (Pro) |
| Resolution verification | Machine-verified — both legs checked to settle on identical criteria before a pair is called an arb | Not advertised |
| Arb pricing basis | Live ask prices, exact per-venue fee model, ranked by annualised return | Not published |
| Trade journal & P&L | Yes — and it is on the free tier | Not advertised |
| Whale / smart-money feed | Yes — $10k+ trades, on the free tier | Not advertised |
| REST API | $0 for 1,000 req/mo · $9.99 for 50,000 · $29.99 for 1,000,000 | Premium $299/mo — 5,000 credits/mo |
| WebSocket streaming | Yes — 3–10 connections by API tier | Not advertised |
| MCP server (Claude, Cursor) | Yes | No |
| Automated execution | No — read-only by design | Yes — Premium bot capability |
We would rather you pick the right tool than churn out of ours in a month.
If you are writing your own bot or dashboard, this is where the two products separate hardest. ArbBets bundles REST access into its $299/month Premium tier with a quota of 5,000 credits per month.
MarketMaster sells the data API separately from the Pro subscription. A free key gives you 1,000 requests per month to build against. $9.99/month raises that to 50,000. $29.99/month takes it to 1,000,000 requests with 10 WebSocket connections.
Put plainly: MarketMaster's free API tier gives you a fifth of ArbBets' $299 monthly quota, and its $9.99 tier gives you ten times that quota for about 3% of the price. If the API is your use case, this is not a close comparison.
$299/mo · 5,000 API credits per month, plus the full sports and prediction scanner and bot execution.
$29.99/mo · 1,000,000 requests per month, 10 WebSocket connections, Python and JavaScript SDKs, MCP server.
It depends on what you trade. ArbBets covers a third venue (Opinion) and does sports arbitrage, which MarketMaster does not. If those matter to you, ArbBets is the better fit. If you trade Kalshi and Polymarket and want the cross-venue math done conservatively, MarketMaster does that at a fraction of the price.
No. As of August 2026 ArbBets starts at $59/month for Basic, and the prediction-market arbitrage scanner sits in the $149/month Pro tier. There is a demo built on a historical snapshot, but no free live account. MarketMaster's scanner, analyzer and trade journal are free with no time limit.
ArbBets includes REST API access in its $299/month Premium tier with 5,000 monthly credits. MarketMaster's API Free key gives 1,000 requests a month at no cost, API Starter is $9.99/month for 50,000 requests, and API Pro is $29.99/month for 1,000,000 requests. If the API is your main use case, the gap is large.
ArbBets advertises automated trading bot capabilities in its Premium tier. MarketMaster is deliberately read-only: it can display your positions from a read-only Kalshi key or public Polymarket wallet, but it cannot trade or move funds. That is a design choice, not a missing feature.
Competitor pricing and features are recorded as published on the dates shown and are not guaranteed to be current. Where a capability is marked “not advertised”, it means we could not find it documented on the vendor’s own site — not that it definitely does not exist. Spotted something wrong? Tell us and we will correct it.
The full scanner and analyzer are free, forever. No card, no trial clock.
MarketMaster is an analytics tool. It does not provide financial advice or guarantee returns, and prediction markets carry real risk of loss.