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Category overview · updated 23 August 2026

Prediction market tools, compared honestly

We make one of the tools on this page, so read it with that in mind. What we have tried to do is state every competitor's pricing and capabilities as they publish them, name the things they do better than us, and link the sources so you can check.

Where the category stands, August 2026

Oddpool has closed to new subscriptions. Its own pricing page says existing accounts continue but new ones cannot be bought — which removes the $30/month arbitrage option from the market.

That leaves a wide gap in the middle. Prediction Hunt is free and covers the most venues. ArbBets starts at $59 and puts prediction-market arbitrage at $149. MarketMaster is $12.99 for arbitrage with a free scanner beneath it.

The category at a glance

Prices as published by each vendor on 23 August 2026. This table changes often; every claim links to a source at the bottom of the page.

Entry price is the cheapest way to use the product at all; arbitrage price is the cheapest tier that includes cross-venue arbitrage scanning.
ToolEntry priceArbitrage priceVenuesOpen to new users
MarketMasterFree forever$12.99/moKalshi, PolymarketYes
Prediction HuntFreeFreeKalshi, Polymarket, PredictIt, ProphetX +Yes
ArbBets$59/mo$149/moKalshi, Polymarket, OpinionYes
OddpoolFree (existing accounts)$30/moKalshi, PolymarketClosed

Read the full comparisons

Each one includes a feature-by-feature table, the case for choosing the other tool, and our sources.

What actually separates these tools

Venue count is the headline number everyone competes on. It is not the one that costs you money when it is wrong.

Questions worth asking any scanner

  • Does it verify that both legs resolve identically? Different sources, cutoff times and tie-breakers turn an apparent arbitrage into a directional bet you did not intend to make.
  • Is it quoting live asks or midpoints? Midpoints overstate every opportunity, because a midpoint is not a price anyone will sell you.
  • Does the fee model match the venue? Kalshi's fee varies with price, so a flat percentage is wrong at the tails — exactly where arbitrage lives.
  • Is the ranking annualised? A three-cent lock that settles tonight beats a five-cent lock that settles in 2027.
  • Are any rows sponsored? If placement can be bought, the ranking is advertising.

How we answer them

  • Machine-verified resolution. An automated verifier compares both venues' criteria and records a verdict. No confirmation, no risk-free label — and ambiguous groups are withheld rather than printed.
  • Live asks only. Arbitrage is priced off executable asks, never midpoints.
  • Exact per-venue fee curves in the maths, not a flat estimate.
  • Ranked by annualised return, not raw spread.
  • Never sponsored. No paid placement in the live feed, at any price.

Also in this category

Tools we have not tested directly, listed because independent roundups cover them and you may want to look: Predictions Terminal (free tier plus a paid plan reported around $49/month), Claw Arbs (automated execution across API-enabled venues), Unusual Predictions and Polymarket Analytics (analytics, both reported around $20/month), and the open-source EdgeHunt and ArbIt projects for people who would rather read the maths than pay for it.

Pricing in that paragraph is as reported by the third-party roundups linked below, not verified by us against each vendor's own site. Treat it as a starting point for your own check.

Questions people actually ask

What is the cheapest prediction market arbitrage scanner?

Among tools open to new customers in August 2026, Prediction Hunt's arbitrage finder is free, and MarketMaster's arbitrage feed is $12.99/month with a free scanner tier beneath it. ArbBets puts prediction-market arbitrage in a $149/month tier and has no free plan. Oddpool's $30/month Pro tier is no longer available to new subscribers.

Is prediction market arbitrage actually risk-free?

No. Two markets can look identical and still settle differently because of different sources, cutoff times or tie-breakers, and a spread quoted at midpoint can vanish before you can hit both legs. Fees differ by venue and, on Kalshi, by price. Any tool that labels an opportunity risk-free without verifying that both legs resolve on identical criteria is overstating what it knows.

How much capital do you need for this to be worth it?

That is your call to make, not ours, and it depends on the spreads you actually capture rather than the ones a scanner advertises. The arithmetic is simple enough to do yourself: a subscription is worth paying for when the edge it surfaces, after fees and after the trades you actually get filled on, exceeds its cost. Start on a free tier and measure before you subscribe to anything.

Which tools cover the most venues?

Prediction Hunt covers the most of those reviewed here — Kalshi, Polymarket, PredictIt, ProphetX and others. ArbBets covers Kalshi, Polymarket and Opinion. MarketMaster and Oddpool cover Kalshi and Polymarket only.

Sources · last verified 23 August 2026

We make MarketMaster, so this page is not independent and does not pretend to be. Everything about a competitor is sourced to that competitor’s own published pages, recorded on 23 August 2026. If we have got something wrong or out of date — including in our favour — tell us and we will fix it.

Try the scanner before you decide.

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MarketMaster is an analytics tool. It does not provide financial advice or guarantee returns, and prediction markets carry real risk of loss.