Kalshi and Polymarket are the two biggest prediction-market venues in 2026. They both let you buy YES/NO contracts on future events. Practically, they're very different platforms.
Where they are and who can use them
Kalshi: US-based. CFTC-regulated exchange. US traders only (geofenced from most other countries). Funded in US dollars via ACH or debit card.
Polymarket: global, built on the Polygon blockchain. Geofenced from the US , US traders cannot legally use it. Funded in USDC (a stablecoin) via crypto wallet. No KYC required for most activity, but IP detection blocks US accounts.
What they list
Kalshi: economic data (Fed, CPI, jobs), weather (NOAA-based), financial indices, crypto price levels, elections, selected sports. The CFTC limits contract types to measurable, data-tied events. No pop culture, no obscure long-tail markets.
Polymarket: everything. Crypto, politics, sports, entertainment, memes, pop culture, one-off events. If there's any public interest, a market probably exists.
Liquidity patterns
Kalshi and Polymarket have different depth profiles. Kalshi tends to have deeper liquidity on economic/weather contracts (their focus). Polymarket dominates political and crypto markets due to scale and US election volume from 2024.
For any given event that's listed on both, the more liquid market usually has tighter spreads and more reliable pricing. See our arbitrage pairs page for real examples.
Settlement
Kalshi: $1 or $0 per contract in USD. Credited within hours of the event resolving.
Polymarket: $1 USDC or $0 USDC per contract. Settled on-chain via optimistic oracle , there's a dispute window during which resolution can be contested. Most markets resolve cleanly; some have had controversy.
Fees
Kalshi: 1-7% per trade, sliding based on price level.
Polymarket: 0% maker fee, 0% taker fee on most markets, but network gas costs for every on-chain interaction ($0.01-0.50 typical).
Trust models
Kalshi is a regulated US exchange. If Kalshi goes bankrupt, customer funds are segregated under CFTC rules, and there's a legal structure for recovery.
Polymarket is a self-custody DeFi protocol. Your USDC is in your wallet (not Polymarket's custody). The smart contracts have been audited, but they're smart contracts , bugs or exploits are theoretically possible. No regulator to call if something goes wrong.
For traders: which to use
Simple rule:
- US resident: Kalshi. It's your only legal option.
- Outside US: choose based on what's listed. Polymarket has broader catalog; Kalshi (where available to non-US residents via specific product lines) is more limited.
For researchers: use both
Our arbitrage page shows every pair of similar markets listed on both platforms with their price disagreements. The gaps are sometimes signal (one market is slow to react) and sometimes noise (resolution criteria differ subtly). Either way, having both lets you triangulate.