GUIDE · LUNARSHADOW AI · UPDATED
Kalshi vs Polymarket.
Same contracts, different plumbing.
Both venues list yes-or-no contracts on real-world events. They differ in who can use them, how money moves in and out, and how fees are charged. Here is how they compare.
The short version
On both venues a contract pays $1 if its outcome happens and nothing if it does not, so a price of 30¢ reads as roughly a 30% market-implied chance. Kalshi is a US exchange regulated by the Commodity Futures Trading Commission (CFTC): you open a verified account and trade in US dollars. Polymarket's main exchange runs on the Polygon blockchain and settles in USDC, a dollar stablecoin, and it blocks users in restricted regions, including the United States.
Who can use each one
Kalshi
Kalshi is registered with the CFTC as a designated contract market. Accounts require identity verification, and Kalshi sets its own eligibility rules. Check Kalshi's help center for the current requirements before you sign up.
Polymarket
The international exchange at polymarket.com uses crypto wallets and restricts access from a list of countries, including the US. See Polymarket's geographic restrictions. Polymarket also runs a separate CFTC-regulated app for US users, with its own account checks, markets and rules; it is a different platform from the international exchange.
Prediction markets are also the subject of disputes with some US states, so access can change. Check each venue's current terms for where you live.
How you fund an account
Kalshi
Your balance is held in US dollars in your Kalshi account. Kalshi lists its current deposit and withdrawal methods, and any fees for them, in its help center.
Polymarket
On the international exchange your balance is USDC on Polygon, held in a wallet. Polymarket charges no fee to deposit or withdraw USDC, though the services you use to move funds may charge their own. Polygon transactions also need a small amount of POL for network fees.
Trading fees
Both venues charge more on trades priced near 50¢, where the outcome is least certain, and less on trades priced near either end.
Kalshi
The general fee on an order that trades immediately is 0.07 × contracts × price × (1 − price), rounded up to the next cent. That works out to 1.75¢ per contract at a 50¢ price and about 0.63¢ at 90¢. Orders that rest on the book can pay a smaller fee on some markets, and some series use different rates. The official fee schedule is the source of truth; our Kalshi fees guide works through examples.
Polymarket
Only orders that take liquidity pay a fee: shares × rate × price × (1 − price). Orders that rest on the book pay nothing. The rate depends on the market category: 0.04 for politics, finance, tech and mentions; 0.05 for sports, economics, culture, weather and other; 0.07 for crypto; geopolitics markets are free. At a 50¢ price that is 1¢, 1.25¢ or 1.75¢ per share. See Polymarket's fee documentation, or our Polymarket fees guide.
Fee rates change. The figures above come from each venue's published schedule as of October 2026.
How trades settle
Kalshi
Kalshi matches orders and settles each market under its published rules. Payouts land in your Kalshi account balance.
Polymarket
Orders are matched by Polymarket and settled on the Polygon blockchain. Each market resolves under its stated rules, and winning shares are redeemed for USDC.
Automating either one
Both venues offer APIs, so trading can be automated. On Kalshi a bot works through an API key you create in your Kalshi profile; on Polymarket it trades from a wallet that signs its orders.
LunarShadow AI runs hosted bots on both. The Kalshi bot trades your own Kalshi account through your API key. The Polymarket bot uses a wallet the platform creates for you, funded with USDC on Polygon or with SOL through the bridge. Either way you set position sizing before switching it on, and on Kalshi you can also set a daily loss cap. See how it works.
Which one fits you
If you want a US-regulated account funded in dollars, Kalshi is the simpler path. If you are outside Polymarket's restricted regions and comfortable holding USDC in a wallet, the international Polymarket exchange has its own wide range of markets. Many traders watch both.
Prediction markets can lose money on either venue, and automation does not change that.