Prediction Market Apps Compared: Fees, Liquidity and Settlement

There is no single best prediction market app. The right one depends on four concrete things: how a venue charges you, how it decides who won, what kinds of markets it lists, and whether its data is open enough to check. The apps most people mean when they search this are Kalshi and Polymarket among the larger names, with Manifold and a handful of smaller venues rounding out the field, and they differ most on mechanics rather than on branding.

A prediction market is a place to trade contracts that pay out based on whether a stated event happens, like an insurance policy you can buy and sell before the outcome is known. The price of a "yes" contract, quoted between roughly 0 and 100 cents, reads as the market's implied probability. If "yes" trades at 60 cents, the crowd is pricing the event at about 60 percent. If you want the underlying mechanics before comparing apps, start with how prediction markets work.

Key takeaways

• The comparison that matters is fee structure, settlement and resolution, market breadth, and data transparency, not which app has the slickest interface.
• Fees are charged in different places (per trade, on winnings, or baked into the spread), so the same bet can cost different amounts on different venues.
• Some venues settle to an official source with clear rules; others rely on a resolver process. How a market resolves is the single most important thing to read before you trade it.
• Regulatory category varies: some venues operate as CFTC-regulated exchanges, others as crypto-native platforms, and that shapes who can access them.
• Onchain venues publish trades to a public ledger, which makes their activity independently checkable in a way most centralized apps do not offer.

Start with how the app charges you

Fees are the first thing to compare because they are the one cost you pay every time regardless of whether you win. Prediction market apps take their cut in three different places, and knowing which model an app uses tells you the real price of a trade.

The three common models:

• Fee on the trade. A charge applied when you buy or sell a contract. Kalshi publishes a variable trading fee in its fee schedule that scales with the contract price, so it is cheapest on very cheap or very expensive contracts and most expensive near 50 cents.
• Fee on winnings or withdrawals. Some venues take nothing on entry and a percentage of profit or a flat withdrawal cost instead.
• Cost in the spread. On many onchain venues the trading fee is low or zero, and your real cost is the gap between the buy and sell price (the spread), plus the small network fee, called gas, that any blockchain charges to process a transaction. Polymarket documents its market structure and fees in its docs.

Here is why the fee model changes the answer. A fee-on-trade schedule like Kalshi's is designed to peak in the middle of the price range. The pattern, in plain terms, looks like this per contract size at different contract prices:

The exact numbers change with each venue's published schedule, so read the current schedule before you trade. The takeaway holds across fee-on-trade venues: per contract, the fee term is largest near 50 cents, and a long-shot or near-certain market is where it is cheapest. A spread-based onchain venue behaves differently, because your cost tracks liquidity rather than the contract price.

Read the settlement rules before anything else

Every prediction contract needs a final answer: did the event happen or not. How a venue produces that answer is where apps differ most, and it is the difference between a market you can trust to pay out cleanly and one you cannot.

Broadly there are two approaches. A regulated exchange typically settles to a named, official source specified in the contract terms, the way a futures contract settles to a published reference price. A crypto-native venue often settles through a resolver or oracle, a process that reports a real-world outcome onto the blockchain so the smart contract (self-executing code that holds the funds and pays winners) can pay out automatically. Polymarket, for example, uses the UMA optimistic oracle, documented at UMA's docs, where a proposed outcome stands unless someone disputes it within a window.

The category-level lesson for choosing an app: ambiguous markets are where settlement disputes happen. A question with a crisp, official data source ("will this index close above X on this date") resolves cleanly almost everywhere. A question phrased loosely, or one whose resolution source is unclear, carries settlement risk on any venue no matter how good the app looks. Read the resolution criteria of the specific market, not just the venue's reputation.

Market types and who can access them

Apps also differ in what they let you trade and where you are allowed to trade it. Some venues focus on a defined set of regulated event contracts across economics, weather, and finance. Others list a much wider, community-created range. The trade-off is coverage versus curation: a broad venue has a market for almost anything, while a curated venue lists fewer markets with clearer terms.

Access depends on regulatory category, which varies by venue and by where you live. Some operate as exchanges overseen by the U.S. Commodity Futures Trading Commission; others are crypto-native and restrict access by jurisdiction. The legal picture is genuinely unsettled and moves quickly, so treat any venue's current status as something to verify rather than assume. For the state of play, see whether prediction markets are legal where you are and the broader question of how exotic event-contract products get regulated. None of this is legal advice; it is a description of a moving target.

Whether you can check the app's own numbers

A quieter differentiator is transparency of activity. Onchain venues write every trade to a public blockchain, which means anyone can independently reconstruct volumes and prices rather than take a dashboard's word for it. Centralized venues publish what they choose to publish. For a journalist, a regulator, or a careful trader, that difference matters when you want to verify a claim about how active a market really is.

There is a practical catch. Raw onchain records for a venue like Polymarket arrive as low-level events (contract addresses, token IDs, transfer logs) that do not, on their own, tell you which market a trade belongs to, what the outcome was, or the dollar value at the time. To turn that into a comparable picture across venues, each trade has to resolve to the same fields: market, outcome, side, price, size, USD value, and settlement status. Allium is a data layer for reading these markets, not a venue, broker, or advisor. It maintains normalized prediction-market datasets, including Kalshi and Polymarket, and publishes prediction-market dashboards built on that standardized data, so activity across venues can be read on the same terms.

A short checklist before you pick one

• The fee schedule and the cost on a real position at the intended price are the first things to check.
• Read the resolution criteria of the exact market, including the named settlement source.
• Confirm the venue's regulatory category and whether it is open to you where you live.
• Check whether the venue's activity is publicly verifiable or reported only by the venue itself.

Get those four right and "best" stops being a matter of taste. It becomes the venue whose mechanics fit the specific market you want to trade.

Frequently asked questions

Is Kalshi or Polymarket better?

They differ on mechanics rather than quality. Kalshi operates as a CFTC-regulated exchange with a published trading fee that peaks near mid-range contract prices and settlement to named official sources. Polymarket is crypto-native, typically with low or zero trading fees where your cost sits in the spread plus network gas, and settles through the UMA optimistic oracle. The better choice depends on the market you want, your location, and whether you value regulated settlement or open onchain verifiability.

Do prediction market apps charge fees?

Yes, but in different places. Some charge a fee on each trade that scales with the contract price, some take a cut of winnings or withdrawals, and many onchain venues charge little on the trade itself while your real cost sits in the bid-ask spread plus a small blockchain network fee called gas. Always compute the cost on a real position at your intended price rather than comparing headline fee numbers.

What does it mean when a prediction market settles?

Settlement is the process of deciding the final outcome of a contract and paying out. Regulated exchanges usually settle to a named official data source specified in the contract terms. Crypto-native venues often use a resolver or oracle that reports the real-world result onto the blockchain so a smart contract can pay winners automatically. Reading the exact resolution criteria of a market before trading is the most important step, because loosely worded questions carry settlement risk on any venue.

Are prediction market apps legal to use?

It depends where you are and which venue you use. Some venues operate as exchanges overseen by the U.S. Commodity Futures Trading Commission, while others are crypto-native and restrict access by jurisdiction. The regulatory picture is unsettled and changes quickly, so verify a venue's current status and your own eligibility rather than assuming. This is a description of the state of play, not legal advice.

Can I verify how much activity a prediction market really has?

On onchain venues, yes, in principle. Every trade is written to a public blockchain, so anyone can reconstruct volumes and prices independently. The raw records are low-level and need to be normalized into readable fields (market, outcome, price, size, USD value) before they are comparable across venues. Centralized venues publish what they choose to, so independent verification is harder there.

How does an event contract differ from a fixed-odds bet?

A prediction market lets you trade contracts on the outcome of an event at prices that move with supply and demand, and you can usually sell your position before the event resolves. Sportsbook odds are set by the operator and you generally hold a fixed bet to the finish. Prediction market prices double as a live implied-probability reading of the event, which sportsbook payouts do not cleanly provide.

Interested in learning more about Allium’s prediction market data? Speak to someone on the team.

Allium provides onchain data infrastructure. Companies named in this article may be Allium customers, prospects or commercial counterparties. This article is informational only and is not investment, legal or tax advice. Data and information last reviewed: September 23, 2026.