Prediction market guides
100 explainers on how prediction markets price an event, how to read a probability, why two venues disagree about the same question, and what these numbers cannot tell you. Written by the ProudGlobeHead Markets Desk to go with the live data on this site. Educational only — nothing here is financial advice.
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Ten subjects, each one a short course you can read in order
10 guidesPrediction Market BasicsWhat a prediction market is, how a contract pays, and how to read one without guessing.10 guidesPrices and ProbabilityTurning a price in cents into a probability, and understanding what that number actually claims.10 guidesKalshiThe regulated US exchange: contract structure, settlement sources, fees and the things that surprise people.10 guidesPolymarketThe on-chain venue: USDC collateral, resolution by oracle, and how its order book behaves in practice.10 guidesCross-Market GapsWhy two venues price the same event differently, and what a gap between them is really worth.10 guidesForecasting and CalibrationBase rates, scoring rules, calibration curves, and telling a good forecast from a lucky one.10 guidesOrder Books and LiquiditySpreads, depth, slippage, market making and what settlement does to a position you still hold.10 guidesWhat Markets PriceElections, macroeconomic releases, sport, weather, crypto and company events, one category at a time.10 guidesData and AutomationPublic APIs, historical series, backtesting honestly, and building something on top of market data.10 guidesRisk and CostsFees, capital lockup, resolution risk, behavioural traps and the limits of any measured edge.
Latest
Newest guides across every subject
Kalshi · 3 min readWhat Kalshi Is, and What Makes It DifferentKalshi is a US federally regulated exchange for event contracts. Here is what that regulation actually changes about the product you trade on.
Kalshi · 3 min readHow a Kalshi Contract Is Put TogetherSeries, event, strike and settlement rule. Taking apart a single Kalshi market so the ticker stops looking like noise and starts reading as a sentence.
Kalshi · 3 min readHow Kalshi Fees Work, and Where They Hurt MostKalshi's trading fee is not a flat percentage. It is shaped like a curve that peaks at fifty cents, and that shape changes which trades are worth doing.
Kalshi · 3 min readWhere Kalshi Settlement Numbers Actually Come FromA contract is only as good as the source that settles it. What Kalshi names as its sources, how revisions are handled, and what happens when data goes missing.
Kalshi · 3 min readWhat Kalshi Lists, and What It Does NotA tour of the categories a regulated event exchange carries, why the list looks the way it does, and which questions are structurally absent from it.
Kalshi · 3 min readOrder Types on Kalshi and When to Use EachLimit, market, resting and immediate. A short guide to expressing a view on an event exchange without paying more than the view is worth.
Kalshi · 3 min readThe Life of a Kalshi Market, From Listing to SettlementA market is not one thing over its life. Liquidity, spreads and what the price means all change between listing day and the final hour.
Kalshi · 3 min readWorking With Kalshi's Public Market DataWhat the public endpoints expose, what they do not, and how to build something on top of them without hammering the service or fooling yourself.
Kalshi · 3 min readWhat CFTC Regulation Means for an Event ExchangeA designated contract market licence changes what can be listed, how funds are held and who can participate. A plain explanation of the parts that affect users.
Kalshi · 3 min readThings That Surprise People on KalshiThe settlement quirks, fee shapes and structural details that catch new users out, collected in one place so they catch you somewhere cheaper.
Polymarket · 3 min readWhat Polymarket Is, and How On-Chain Changes ItPolymarket settles event contracts on a blockchain with stablecoin collateral. Here is what that architecture changes about pricing, resolution and risk.
Polymarket · 3 min readHow Polymarket Resolves a MarketAn optimistic oracle proposes an answer, a window opens for challenges, and a dispute process exists behind it. What each stage means for a position you hold.Read these against live numbers
What is moving
Every guide about movement has a live counterpart: the biggest probability changes on both venues, ranked by significance rather than by size.
Top movers →Where venues disagree
The gap board shows the same event priced on Kalshi and Polymarket at once, with the theoretical cross-market edge in each difference.
Gap board →How it is calculated
Every score, grade and edge on this site is defined in writing, including the cases where the number should not be trusted.
Methodology →