Two platforms dominate prediction markets right now. Kalshi has been the US leader for years. Polymarket just returned to American traders after a three-year ban. Both are CFTC-regulated, both are seeking $20 billion valuations, and both are locked in the same legal battle with state regulators. But the trading experience, fee structure, and target users are fundamentally different. We break down where each platform wins, where it loses, and which one makes more sense for your trading style.
Quick Comparison
| Feature | Kalshi | Polymarket |
|---|---|---|
| Founded | 2018 | 2020 |
| Founders | Tarek Mansour & Luana Lopes Lara (MIT) | Shayne Coplan |
| Headquarters | New York, NY | New York, NY |
| Regulation | CFTC-designated contract market (DCM) | CFTC-regulated via QCEX acquisition |
| Settlement currency | USD | USDC (stablecoin) for global; USD for US platform |
| Last valuation | $11B (Dec 2025) | $9B (Oct 2025, ICE investment) |
| Seeking valuation | ~$20B | ~$20B |
| Total funding | ~$1.59B | ~$1B+ (incl. up to $2B from ICE) |
| Key investors | Paradigm, Sequoia, a16z, CapitalG, ARK Invest | Intercontinental Exchange (NYSE parent), Founders Fund, Dragonfly |
| 2025 trading volume | $22.88B (notional) | $7B+ monthly at peak (Feb 2026) |
| Revenue run rate | ~$1.5B annualized (March 2026) | Not publicly disclosed |
| Taker fees | Variable (formula-based, max ~$0.02/contract) | 0.10% on US platform; varies on global |
| Maker fees | Reduced; rebates up to 1% | Rebates of 0.10% on US platform |
| Deposit methods | ACH, wire, debit card, PayPal, Venmo, crypto | Debit card, ACH, wire (US); USDC/crypto (global) |
| Interest on idle cash | ~4% APY | No |
| Mobile app | iOS and Android | iOS and Android |
| Demo account | Yes | No |
| API quality | Functional, adequate | Comprehensive — three separate APIs, WebSocket, SDKs |
| Robinhood integration | Yes (reportedly 50%+ of volume) | No |
Background: How We Got Here
Understanding the competitive dynamics between Kalshi and Polymarket requires a brief look at how each platform arrived at its current position — because their paths couldn't be more different.
Kalshi took the slow, regulated route. Founded in 2018, the company spent years navigating the CFTC approval process before launching publicly in 2021. For most of its early life, Kalshi focused on niche markets — economics, weather, and policy outcomes. The real inflection point came in late 2024 and 2025 when Kalshi won a critical legal battle to list election contracts and then aggressively expanded into sports. Sports now accounts for roughly 90% of Kalshi's revenue. The platform processed $22.88 billion in trading volume in 2025 — a 1,100% year-over-year increase. The Robinhood partnership, which reportedly now drives more than half of Kalshi's volume, brought millions of retail traders into prediction markets for the first time.
Polymarket took the opposite path. It launched as a crypto-native platform in 2020, grew rapidly, got charged by the CFTC in 2022 for operating without registration, paid a $1.4 million fine, and was blocked from serving US users. During its three-year US exile, Polymarket became the world's largest prediction market by volume, peaking at over $3 billion in monthly trading during the 2024 presidential election. The platform's election coverage became so prominent that major media outlets cited Polymarket odds as a real-time gauge of public sentiment.
Polymarket's US return came in late 2025 after acquiring QCEX, a CFTC-registered exchange and clearinghouse, for $112 million. The US platform is now operating under full CFTC oversight through a phased rollout. In October 2025, Intercontinental Exchange — the parent company of the New York Stock Exchange — announced a strategic investment of up to $2 billion in Polymarket. That investment signal alone changed the competitive calculus. Polymarket isn't a scrappy crypto startup anymore; it's backed by the most established exchange infrastructure in finance.
As of March 2026, both companies are reportedly in discussions with investors about new fundraising rounds that could value each at approximately $20 billion.
Fees: Where the Gap Is Widest
Fees are the single largest practical difference between Kalshi and Polymarket for active traders. The two platforms use fundamentally different models, and the cost gap becomes significant at scale.
Kalshi's Fee Model
Kalshi uses a probability-weighted formula: fees scale with the contract price and the number of contracts. The formula is approximately 0.07 × contracts × price × (1 - price). This means fees peak when the contract is priced near $0.50 (maximum uncertainty) and drop toward zero when contracts are near $0.01 or $0.99 (near-certain outcomes).
The maximum fee is roughly $0.02 per contract. Kalshi also differentiates between taker fees (market orders that execute immediately) and maker fees (limit orders that rest on the book). Makers pay less, and high-volume market makers can earn rebates up to 1% through a tiered reward system.
On a $1,000 position at even odds, Kalshi taker fees run approximately $35. On a $10,000 position, you're looking at meaningful fee drag.
Polymarket's Fee Model
Polymarket US charges taker fees of 0.10% (10 basis points) on the total contract premium. Maker orders receive a 0.10% rebate. The global platform still runs zero-fee on most standard markets, with small taker fees only on high-frequency crypto markets (where they peak at 1.56% at 50% probability).
On that same $1,000 position, Polymarket US charges about $1. On $10,000, it's $10. The difference versus Kalshi's $35 and $350 respectively is substantial.
What This Means in Practice
For casual traders making occasional $50-$200 bets, the fee difference is negligible. A few cents here and there won't materially impact your returns.
For active traders moving in and out of positions — especially in sports markets where lines shift rapidly — the gap compounds. A trader executing $50,000 in monthly volume would pay roughly $1,750 in Kalshi taker fees versus approximately $50 on Polymarket US. Over a year, that's a $20,000+ difference in trading costs alone.
Neither platform charges deposit fees for bank transfers. Kalshi charges 2% on debit card deposits. Polymarket's global platform may involve on-ramp fees through providers like MoonPay (up to 4.5%), though direct USDC deposits carry only minimal gas fees.
Liquidity and Market Depth
Liquidity — how easily you can buy and sell contracts at fair prices without moving the market — is critical for any exchange.
As of early March 2026, the two platforms are surprisingly close on key metrics. Open interest on Kalshi sits above $400 million, versus approximately $360 million on Polymarket. Weekly notional volume recently came in at $1.9 billion for Polymarket and $1.87 billion for Kalshi.
But the distribution of liquidity differs by category.
Sports
Kalshi dominates. Sports accounts for roughly 90% of Kalshi's volume, and the platform has the widest sports catalog among prediction markets — NFL, NBA, NCAAB, NHL, soccer, tennis, golf, UFC, and esports, with game outcomes, spreads, totals, player props, and parlays. Kalshi's "Build Your Combo" parlay feature, introduced in 2025, added another angle for sports traders.
The Robinhood integration is a major structural advantage here. Millions of retail users who already have Robinhood accounts can access Kalshi markets without creating a separate account. That distribution channel is hard for Polymarket to replicate.
Polymarket has been expanding its sports coverage but still trails Kalshi in breadth and depth. Polymarket's strength in sports is growing, with the platform increasingly being indexed by odds aggregators and building out its own sportsbook-style offerings, but it hasn't reached Kalshi's level of market variety or volume in this category.
Politics and Elections
Polymarket leads, and it's not particularly close. The platform became the global standard for election market data during the 2024 presidential cycle, and that reputation has carried into 2026. Polymarket's political markets have the deepest liquidity, widest variety of questions, and the most active community of political traders. Google now integrates both Kalshi and Polymarket data into search results and Google Finance, but Polymarket's political markets are generally the reference cited by media outlets.
Kalshi's political markets are solid and growing, but Polymarket's head start in this category — built during the years when Kalshi was primarily focused on economics — gives it a structural advantage that's hard to close quickly.
Economics and Finance
This is Kalshi's original strength. Contracts on Fed rate decisions, CPI prints, GDP releases, and other macroeconomic indicators have been on Kalshi longer than any other platform. The market depth is strong, and contract prices reprice within seconds of major economic data releases.
Polymarket covers similar macro markets, but Kalshi has more granularity and a longer track record in this space.
Crypto
Polymarket has the natural edge here, given its origins as a crypto-native platform. Crypto price prediction markets — particularly high-frequency 15-minute and 5-minute contracts — are a Polymarket specialty that Kalshi doesn't match.
Weather
Kalshi is the only major platform offering meaningful weather prediction markets. Hurricane landfalls, temperature ranges, snowfall totals — this is a niche that Kalshi essentially owns.
User Experience: Two Different Philosophies
Kalshi: The Fintech Approach
Kalshi looks and feels like a modern trading app. Clean interface, dark palette, organized market categories, and a straightforward trading flow. You deposit USD from your bank account, browse markets, and trade. No crypto knowledge required. The learning curve is minimal.
The platform has integrated features designed for the traditional finance audience: a free demo account for practice, interest on idle cash balances (approximately 4% APY), and direct integrations with Robinhood and media platforms like CNN and CNBC.
Kalshi's mobile app is available on iOS and Android. Reviews have noted occasional stability issues — freezing, crashes, and inconsistent price displays — though Kalshi has been responsive to complaints and the app improves with each update.
The community features are limited. Kalshi has an "Ideas" section where users share analysis, but it's not as active or prominent as Polymarket's community engagement.
Polymarket: The Crypto-Native Approach
Polymarket's global platform has always been wallet-first. The traditional flow involved connecting a crypto wallet, depositing USDC, and trading on the Polygon blockchain. For crypto-native users, this is seamless. For everyone else, it was the biggest barrier to entry.
The US platform changes this equation significantly. Polymarket US operates through a CFTC-regulated exchange and supports deposits via debit card, ACH, and wire transfer — no crypto wallet required. Withdrawals process in 1-4 business days depending on the method. The experience is getting closer to a traditional brokerage, though the platform's crypto roots still show in the underlying settlement mechanics.
What Polymarket gets right is community. Every market has a comments section where traders discuss, debate, and share analysis in real time. The platform also has a robust leaderboard system. For traders who value market discussion and social proof alongside their positions, Polymarket's community layer is meaningfully more developed than Kalshi's.
The mobile app is available on both platforms and is generally well-reviewed. Polymarket's app has the advantage of being battle-tested over a longer period on the global platform.
API and Automated Trading
For algorithmic traders, this isn't a close contest. Polymarket's API infrastructure is significantly more comprehensive.
Polymarket's ecosystem is organized across three separate APIs. The Gamma API handles market data, events, and search. The Data API covers positions, trades, leaderboards, and analytics. The CLOB API handles orderbook data, pricing, and trade execution. On top of this, Polymarket offers WebSocket streaming for real-time data, official Python and JavaScript SDKs, and supports community-built tools. The documentation is thorough, and the developer ecosystem is active.
Kalshi's API is functional and covers the basics — market data, order placement, portfolio management, and account operations. It works fine for most automated strategies. But it lacks the breadth of Polymarket's offering, and the documentation is generally considered less comprehensive. Jump Trading operates as a market maker on both platforms, but the tools available to smaller algorithmic traders favor Polymarket.
If API access is a primary consideration — whether for bot trading, data analysis, or building applications on top of prediction market data — Polymarket is the better choice.
Deposits, Withdrawals, and Cash Management
Getting Money In
Kalshi wins on accessibility. You can deposit via ACH (free), wire transfer (free from Kalshi's side), debit card (2% fee), PayPal, Venmo, or crypto. The variety of options means almost anyone with a US bank account can get started quickly. Existing Robinhood users can access Kalshi markets directly without a separate deposit.
Polymarket US now supports debit card, ACH, and wire transfer deposits. The global platform accepts USDC directly or via MoonPay (credit/debit card with up to 4.5% fees) and Coinbase transfers. The US onboarding has improved dramatically since the QCEX acquisition, but Kalshi still offers more deposit flexibility, particularly with PayPal and Venmo.
Getting Money Out
Kalshi processes withdrawals via ACH (free, 1-3 business days). Polymarket US offers withdrawals to debit card (3-4 business days), ACH (3-4 business days), or wire transfer (1 business day). Neither platform charges withdrawal fees on its side, though your bank may apply its own charges.
Interest on Idle Cash
Kalshi pays approximately 3.75-4% APY on uninvested cash balances. For traders who keep significant capital on the platform between trades, this is a meaningful benefit that partially offsets trading fees. Polymarket does not offer interest on balances. Over time, this compounding advantage matters — especially for traders with larger accounts who aren't fully deployed at all times.
Regulation: Same Fight, Different Angles
Both Kalshi and Polymarket operate under CFTC regulation, and both face the same fundamental legal question: can the federal government's authority over prediction markets preempt state gambling laws?
The Trump administration has sided firmly with the platforms. CFTC Chairman Michael Selig has asserted exclusive federal jurisdiction and vowed to fight state enforcement efforts in court. But the state-level pushback is intense and growing.
As of March 2026, the regulatory landscape looks like this: litigation is active in at least eight states. Officials in 11 states have issued cease-and-desist orders to prediction market companies. Court rulings have been mixed — states have won in Nevada and Massachusetts (where judges sided with state gambling regulators), while Kalshi has won in New Jersey and Tennessee. U.S. Representatives have introduced legislation that could restrict prediction market offerings on war and sports. Utah is on the verge of passing a law specifically targeting proposition betting that would impact prediction market sports contracts.
For traders, the practical implication is the same on both platforms: prediction markets are legal at the federal level, but state-level restrictions may apply depending on where you live, and the regulatory landscape is evolving rapidly.
One political wrinkle worth noting: Donald Trump Jr. has invested in Polymarket through his venture capital firm and serves as a strategic advisor for Kalshi. Any CFTC decisions favorable to the industry could have implications for the president's family — a point that has drawn scrutiny from both parties.
Who Should Use Kalshi?
Kalshi is the better platform if you're a US-based trader who wants the simplest possible onboarding with USD deposits and no crypto friction. It's the clear winner for sports traders who want the widest market selection and deepest sports liquidity. Traders who value economics and weather markets will find more depth on Kalshi than anywhere else. Beginners benefit from Kalshi's free demo account — a risk-free way to learn the mechanics. And anyone who parks meaningful capital between trades will appreciate the ~4% APY on idle balances.
Kalshi also wins for users who access prediction markets through Robinhood. If you're already a Robinhood user, trading Kalshi contracts is integrated directly into the platform you already know.
Who Should Use Polymarket?
Polymarket is the better platform if you prioritize low fees above all else — the 0.10% taker fee on the US platform is dramatically cheaper than Kalshi for active traders. It's the definitive choice for political and election market trading, where Polymarket has the deepest liquidity in the world. Crypto-native traders who are comfortable with USDC and wallet-based transactions will find Polymarket's global platform seamless. And if API access and algorithmic trading are your focus, Polymarket's comprehensive tooling is clearly superior.
Polymarket also wins for community-minded traders. The per-market comment sections, leaderboards, and social features create a more engaging experience for people who want to discuss and debate alongside their trading.
International traders outside the US have a more straightforward path on Polymarket's global platform, though Kalshi has been expanding its international availability to 140+ countries.
Can You Use Both?
Yes, and most serious prediction market traders do. The platforms have complementary strengths: Kalshi for sports and economics, Polymarket for politics and crypto. Maintaining accounts on both lets you trade where the liquidity is deepest for any given market and arbitrage price differences between the two exchanges when they appear.
There's no exclusivity requirement. Both platforms support standard KYC verification and USD-based deposits (Polymarket via its US platform). The incremental effort of maintaining two accounts is minimal compared to the benefit of accessing the best liquidity and pricing across the full range of prediction market categories.
The Bigger Picture: Where Prediction Markets Are Heading
The competition between Kalshi and Polymarket is happening against a backdrop of explosive industry growth. Prediction market trading volume grew from approximately $9 billion in 2024 to over $44 billion in 2025 — a 400%+ increase. Monthly volumes have expanded from under $100 million at the start of 2024 to over $13 billion toward the end of 2025. Analysts project the prediction market space could reach $1 trillion in trading volume within the next few years.
Both platforms are no longer operating in a vacuum, either. Crypto.com launched OG, DraftKings and FanDuel are exploring prediction market strategies, Coinbase entered the space in December 2025, and traditional exchanges are embedding probability data into their platforms. The competitive landscape is intensifying.
But the existential risk is regulatory. If states succeed in classifying sports prediction contracts as gambling — which they're actively arguing in multiple courts — both Kalshi and Polymarket could lose access to the category that drives the majority of their revenue. The CFTC has positioned itself as the industry's champion, but the agency's authority is being tested in real time, and Congressional legislation could change the rules entirely.
For now, both platforms are growing fast, both are raising capital at staggering valuations, and both are fighting to define what prediction markets look like in America. The smart bet — if you'll pardon the expression — is that both will exist and thrive in the near term. The question is which one will matter more in three years.
Frequently Asked Questions (FAQ)
Which is better for beginners, Kalshi or Polymarket?
Kalshi. The USD deposit process is simpler, the interface is straightforward, and the free demo account lets you practice without risking real money. Polymarket's US platform has closed the gap on onboarding, but Kalshi's demo mode remains a unique beginner-friendly feature.
Which platform has lower fees?
Polymarket. The US platform charges taker fees of 0.10% with maker rebates of 0.10%. Kalshi's formula-based fees are significantly higher, especially on contracts priced near 50% probability. For active traders, the fee difference is substantial.
Which has better sports markets?
Kalshi. Sports accounts for approximately 90% of Kalshi's volume, and the platform offers the widest selection of sports contracts — including game outcomes, spreads, totals, player props, and parlays. Polymarket's sports coverage is expanding but hasn't reached Kalshi's depth.
Which has better political markets?
Polymarket. The platform became the global standard for election and political market data during the 2024 presidential cycle and maintains the deepest liquidity and widest variety of political contracts.
Is Polymarket legal in the US now?
Yes. Polymarket returned to the US market in late 2025 after acquiring QCEX, a CFTC-registered exchange. The US platform operates under full federal regulatory oversight and is currently in a phased rollout across the country.
Do either platform pay interest on uninvested cash?
Kalshi pays approximately 3.75-4% APY on idle cash balances. Polymarket does not offer interest on balances.
Can I use both platforms at the same time?
Yes. Most active prediction market traders maintain accounts on both platforms to access the best liquidity and pricing across different market categories. There's no exclusivity requirement.
Which platform is better for automated or API-based trading?
Polymarket. Its API ecosystem includes three separate APIs (Gamma, Data, and CLOB), WebSocket streaming, official SDKs, and comprehensive documentation. Kalshi's API is functional but less robust.
Are prediction markets legal in every US state?
Both platforms operate under CFTC federal regulation, which theoretically allows nationwide operation. However, multiple states have challenged this, arguing that sports prediction contracts constitute gambling. As of March 2026, litigation is active in at least eight states, and enforcement actions have been issued in 11 states. The legal landscape is evolving and varies by state.
Which platform should I choose if I only want to pick one?
If you're primarily a sports trader who wants the simplest setup with USD deposits: Kalshi. If you're primarily interested in politics, crypto markets, or low-cost active trading: Polymarket. If you're unsure, start with Kalshi's free demo account to learn the mechanics, then open a Polymarket account when you're ready to explore more markets.
