Kalshi vs Polymarket: We Trade Both — Here's the Honest Verdict
Detailed comparison of Kalshi and Polymarket — fees, markets, regulation, and which prediction market platform is right for you.
The two biggest names in prediction markets right now are Kalshi and Polymarket. One is a CFTC-regulated exchange built for US traders. The other is a crypto-native platform with global reach and massive liquidity on headline events. If you are deciding where to put your money — or whether to use both — the differences between these two platforms matter more than most comparisons let on.
We trade actively on both. This is not a surface-level overview pulled from marketing pages. This is a practical comparison from the perspective of traders who have placed thousands of contracts on each platform, dealt with their quirks, and learned where each one excels and falls short.
Head-to-Head Comparison
| Feature | Kalshi | Polymarket |
|---|---|---|
| Regulation | CFTC-regulated (DCM) | Unregulated (crypto-native) |
| Jurisdiction | US residents only | Global (no KYC for basic use) |
| Deposit Currency | USD (ACH, wire, debit card) | USDC on Polygon |
| Trading Fees | ~1-2 cents/contract (maker-taker) | No explicit fees (cost in spread) |
| Withdrawal Fees | None | Gas fees only (negligible on Polygon) |
| Market Types | Weather, economics, crypto, politics, sports, financials | Politics, crypto, current events |
| API Access | REST + WebSocket (well-documented) | CLOB API (crypto-native) |
| Order Types | Market and limit orders | Market and limit orders |
| Liquidity | Growing; strong on popular markets | Highest in prediction markets |
| Fund Protection | Segregated customer accounts | None (self-custody via wallet) |
| Mobile App | iOS and Android | Web-based (mobile responsive) |
| KYC Required | Yes (US identity verification) | No (for basic trading) |
Regulation and Trust
This is the single most important difference between the two platforms, and it should be the first thing you evaluate.
Kalshi is a designated contract market regulated by the Commodity Futures Trading Commission. That means segregated customer funds, audited settlement sources, defined dispute resolution processes, and real legal accountability. If Kalshi mishandles your funds or resolves a market incorrectly, you have a regulatory body to escalate to. For US-based traders putting meaningful capital into prediction markets, this is not a nice-to-have — it is a fundamental requirement.
Polymarket operates outside of any regulatory framework. It is built on Polygon, an Ethereum Layer 2 network, and uses USDC as its settlement currency. There is no deposit insurance, no segregated accounts, and no government agency overseeing operations. Your funds sit in a smart contract, and if something goes wrong — a dispute over market resolution, a platform shutdown, a regulatory crackdown — you have limited recourse.
What This Means in Practice
For US residents, the regulatory question is not abstract. Trading on an unregulated offshore platform carries legal gray-area risk. Kalshi eliminates that concern entirely. For international traders who cannot access Kalshi, Polymarket is often the only viable option with serious liquidity.
If you are in the US and choosing between the two, Kalshi’s regulatory status alone is a strong argument for making it your primary platform.
Fees and Cost of Trading
The fee structures are fundamentally different, and understanding them is critical to knowing where your strategies will actually be profitable.
Kalshi Fees
Kalshi uses a maker-taker model. Taker fees max out at roughly 1.75 cents per contract (on contracts priced near 50 cents) and drop significantly on contracts priced near the extremes. Maker fees are approximately one-quarter of taker fees. There are no deposit fees, no withdrawal fees, and no inactivity charges.
The fees are transparent and predictable, but they add up. On a round trip — buying and then selling a position — you pay fees on both sides. For strategies with thin edges, this is a constant headwind. A 3-cent mispricing can lose more than half its value to fees before you see a profit.
Polymarket Fees
Polymarket charges no explicit trading fees. Instead, the cost of trading is embedded in the bid-ask spread. In practice, takers pay roughly 1% depending on liquidity conditions. On highly liquid political markets, the effective cost can be lower. On thinner markets, it can be higher.
Gas fees on Polygon are negligible — typically fractions of a cent per transaction. The hidden cost is the crypto onramp: if you are converting USD to USDC and bridging to Polygon for the first time, there are exchange fees and potential slippage along the way.
Which Is Cheaper?
For small to medium trades on liquid markets, the costs are roughly comparable. For high-frequency strategies or trades on contracts priced near 50 cents, Polymarket’s spread-based model can be slightly cheaper than Kalshi’s explicit per-contract fees. For contracts priced near the extremes (under 15 cents or above 85 cents), Kalshi’s fees drop substantially and can be the cheaper option.
The real difference is transparency. With Kalshi, you know exactly what you are paying. With Polymarket, the cost depends on the spread at the moment you trade.
Market Selection
This is where the two platforms diverge significantly.
Kalshi’s Breadth
Kalshi offers the widest range of market categories of any prediction market platform. You can trade contracts on daily weather outcomes, economic data releases (CPI, jobs reports, Fed decisions), S&P 500 and Nasdaq price ranges, Bitcoin and Ethereum prices, political events, sports outcomes, and various current-events markets.
This breadth matters for active traders. If your edge is in macroeconomic data, weather modeling, or financial markets, Kalshi is the only platform that offers structured contracts in those categories. Our Kalshi review covers each market type in detail. The diversity also allows you to spread risk across uncorrelated market types rather than concentrating everything in politics or crypto.
Polymarket’s Depth
Polymarket’s market selection is narrower but deeper where it counts. The platform focuses primarily on political events, crypto-related outcomes, and high-profile current events. What it lacks in breadth, it makes up for in liquidity on its core markets. During major political cycles, individual Polymarket markets can see tens of millions of dollars in daily volume — numbers that Kalshi cannot match on any single market.
If you primarily trade political or crypto-related events and want the deepest possible order book, Polymarket is the better venue for those specific categories.
Deposits and Getting Started
Kalshi: Traditional Finance Rails
Getting started on Kalshi feels like opening a brokerage account. You complete KYC with your name, address, SSN, and government ID. Verification is usually fast. You deposit USD via ACH (free, 1-2 business day settlement), wire transfer, or debit card (instant with a small fee). Withdrawals are free via ACH.
The entire process is familiar to anyone who has used a bank or brokerage. No crypto wallets, no bridging, no token swaps.
Polymarket: Crypto-Native Workflow
Polymarket requires a crypto wallet (MetaMask or similar) and USDC on the Polygon network. If you already hold USDC and are comfortable with DeFi workflows, setup takes minutes. If you are new to crypto, there is a real learning curve: you need to acquire USDC, bridge it to Polygon, connect your wallet, and approve the smart contract interactions.
Polymarket has added fiat onramp options that simplify this process, but it is still meaningfully more friction than depositing USD into a bank-connected Kalshi account. For traditional traders and beginners, this barrier is significant.
User Experience and Interface
Both platforms offer functional trading interfaces, but they serve different audiences.
Kalshi’s web interface is clean and straightforward. Markets are organized by category, the order book is clearly displayed, and placing orders is intuitive. The mobile app covers the basics for on-the-go trading. The interface is not as feature-rich as professional trading platforms, but for prediction market trading it gets the job done without unnecessary complexity.
Polymarket’s interface leans into a modern, crypto-native aesthetic. Market pages show trading volume, price charts, and the order book. The experience is smooth for anyone familiar with DeFi platforms. One advantage is that Polymarket’s interface tends to surface trending and high-volume markets more effectively, which helps with market discovery.
Neither platform offers advanced charting, custom alerts, or sophisticated order types natively. If you want those features, you will need to build them yourself via each platform’s API.
Liquidity: The Deciding Factor for Large Traders
For traders moving meaningful size, liquidity is often the deciding factor.
Polymarket wins on raw liquidity for its core markets. Political and crypto event markets regularly have deep order books with tight spreads. You can enter and exit five-figure positions without significant slippage on popular markets.
Kalshi’s liquidity has improved substantially over the past year but remains thinner on most individual markets. High-profile political markets, daily S&P 500 contracts, and sports markets have reasonable depth. Niche weather markets, far-dated economics contracts, and less popular events can have wide spreads and limited order book depth.
If you are trading small to medium positions across diverse market types, Kalshi’s breadth gives you more opportunities. If you are concentrating large capital on a few high-conviction political or crypto trades, Polymarket’s liquidity gives you better execution.
API and Algorithmic Trading
Both platforms offer API access, but the experience differs.
Kalshi’s API is RESTful with WebSocket support for real-time data. It is well-documented, reliable, and designed for automated trading. Rate limits are reasonable, and the authentication system is straightforward. For developers and quant traders, Kalshi’s API is production-grade.
Polymarket’s CLOB (central limit order book) API is functional and supports programmatic trading, but the crypto-native infrastructure adds complexity. You are interacting with smart contracts, managing gas, and dealing with blockchain-specific edge cases. If you are already building in the crypto ecosystem, this is familiar territory. If you are coming from a traditional finance or Python scripting background, there is additional overhead.
For most developers who want to build trading bots or automated strategies, Kalshi’s API has a lower barrier to entry and a more conventional developer experience. Our developer’s guide to prediction market APIs walks through the code for both platforms.
Key Takeaways
Choose Kalshi if:
- You are a US resident and want the security of CFTC regulation
- You want to trade across diverse market categories — weather, economics, financials, and politics
- You prefer depositing and withdrawing in USD with no crypto complexity
- You are building automated trading strategies and want a well-documented, conventional API
- Regulatory protection and fund safety are priorities
Choose Polymarket if:
- You need maximum liquidity on political and crypto event markets
- You are based outside the US and cannot access Kalshi
- You are comfortable with crypto wallets and USDC
- You want to trade large positions on headline events with minimal slippage
- You prioritize global access over regulatory protection
Use both if:
- You are a US-based trader who wants Kalshi’s regulatory safety and market diversity as your primary platform, but also wants access to Polymarket’s deeper liquidity on major political events
- You are looking for cross-platform arbitrage opportunities where the same event is priced differently on each exchange
If you are new to event contracts entirely, our beginner’s guide to prediction markets covers the fundamentals. For most US-based traders getting started with prediction markets, Kalshi is the safer and more practical starting point. The regulation, USD deposits, and broad market selection make it the lower-friction choice. Add Polymarket when you have a specific reason to — whether that is liquidity, a market that only exists there, or a price discrepancy worth capturing. The two platforms complement each other well, and serious prediction market traders in 2026 should know their way around both.