Yes — Kalshi is a designated contract market (DCM) regulated by the US Commodity Futures Trading Commission (CFTC). It operates off-chain in USD, with trades settled through its own exchange infrastructure.

Guide

Polymarket vs Kalshi: what's the difference?

Q: Can I get data from both Polymarket and Kalshi in one API?

Yes. Idmon normalises signals from both platforms — whale flow, movers, mispricing — into a single schema, delivered by REST, WebSocket, or signed webhooks from https://api.idmon.io. Public endpoints are free at 60 requests/min with no signup required.

Q: Which has better liquidity — Polymarket or Kalshi?

Liquidity varies by market and time. Both platforms have grown significantly, but comparisons depend on the specific market type and event. Rather than cite figures that will quickly go stale, check each platform's current top markets directly.

20 June 2026 · 6 min read

Polymarket and Kalshi are the two most-discussed prediction markets right now, but they're built on fundamentally different foundations — different regulation, different settlement, different infrastructure. This page explains what each is, how they compare, and what that means if you're trying to get data from both.

This is informational only. Nothing here is financial or legal advice. Regulatory situations evolve — check the current position in your own jurisdiction before using either platform.

What is Kalshi?

Kalshi is a US-based prediction-market exchange, regulated by the Commodity Futures Trading Commission (CFTC) as a designated contract market. That makes it the first federally regulated event-contract exchange in the US.

It operates entirely off-chain: accounts are funded and settled in USD, trades happen on Kalshi's own matching infrastructure, and you don't need a crypto wallet to participate. Markets cover elections, economics, weather, Fed decisions, and a range of other event categories.

What is Polymarket?

Polymarket is a crypto-native prediction market running on the Polygon blockchain. Trades settle in USDC (a USD-pegged stablecoin), and the resolution of each market is anchored on-chain — meaning the outcome record lives on a public blockchain rather than inside a private database.

Because it's on-chain and global by design, Polymarket's regulatory situation — including its availability for US users — has changed over time and continues to evolve. We won't try to characterise its current legal status definitively here; check directly and check in your jurisdiction.

Polymarket tends to run a large number of markets across politics, crypto, sports, science, and current events, and is often cited for its volume on high-profile political questions.

How they compare

Dimension	Kalshi	Polymarket
Regulation	CFTC-regulated DCM (US)	Crypto-native, global; regulatory status for US users has changed over time — verify in your jurisdiction
Settlement currency	USD (fiat)	USDC (stablecoin on Polygon)
Infrastructure	Off-chain; Kalshi's own exchange	On-chain; Polygon blockchain
Resolution record	Kalshi's exchange records	On-chain (verifiable on Polygon)
Account type	Standard brokerage-style account (USD)	Crypto wallet + USDC
Market categories	Elections, economics, weather, Fed, more	Politics, crypto, sports, science, current events, more
Data / API	REST API (key required for most endpoints)	Gamma API, CLOB API, Data API (largely free)

Neither is strictly "better" — they serve overlapping but distinct use cases, and the right choice depends on where you are, what you're trading, and what your tooling looks like.

Getting data from both

If you're building with prediction-market data, Polymarket and Kalshi both expose APIs — but they're shaped very differently.

Polymarket gives you three endpoints: Gamma (markets and metadata), CLOB (the order book, trades, and a WebSocket for real-time prices), and a Data API for historical trades. Most of it is free without a key.

Kalshi's API is REST-based and covers markets, positions, and order placement — but key access and rate limits apply more broadly. The schema is entirely different from Polymarket's.

The practical problem: if you want signals from both in one pipeline, you're maintaining two separate ingestion stacks, reconciling different market structures and outcome schemas, and — hardest of all — getting resolution truth you can actually trust. Polymarket's on-chain settlement is a meaningful advantage here, but only if something reads and interprets those on-chain records for you.

One normalised API across both

Idmon sits across both platforms and gives you the part you'd otherwise build yourself. Rather than running two ingestion pipelines and wiring your own signal logic, you get:

Normalised real-time signals — whale flow, movers, and mispricing indicators across Polymarket and Kalshi, in one consistent schema.
Calibrated resolution labels — for Polymarket, resolution is on-chain-anchored; for Kalshi, calibrated. Either way, you're not relying on scraped "resolved" fields that drift.
Three delivery modes — REST, WebSocket, and signed webhooks — so you pull, stream, or receive pushes depending on what your system needs.

The base URL is https://api.idmon.io. A quick read of recent signals across both platforms looks like this:

# recent signals across Polymarket + Kalshi
curl -H "Authorization: Bearer YOUR_KEY" \
  "https://api.idmon.io/api/alerts/recent?limit=20"

Code examples in curl, Python, and Node are in the examples repo. Full schema and WebSocket / webhook details are in the API docs.

Try it free, no signup. Idmon's /public/* endpoints are open at 60 requests/min — no key, no account. When you need real-time push, higher throughput, calibrated resolution, or a commercial licence, request a key and you'll be live within a business day.

FAQ

What is the main difference between Polymarket and Kalshi?

Kalshi is a US-based, CFTC-regulated exchange that trades off-chain in USD. Polymarket is crypto-native, running on the Polygon blockchain and settling in USDC on-chain. Their regulatory frameworks, settlement currencies, and technical architectures are meaningfully different. Availability of either platform may depend on your jurisdiction — check where you are.

Is Kalshi regulated?

Yes. Kalshi is a designated contract market (DCM) regulated by the US CFTC. It operates off-chain in USD with trades settled through Kalshi's own exchange infrastructure — no crypto wallet required.

Is Polymarket available in the US?

Polymarket's availability and regulatory status for US users has changed over time. Rather than state a definitive current position here, check Polymarket's own terms and the current regulatory situation in your jurisdiction before using the platform.

Can I get data from both Polymarket and Kalshi in one API?

Yes — that's what Idmon is for. It normalises signals from both platforms into a single schema and delivers them by REST, WebSocket, or signed webhooks. Public endpoints at https://api.idmon.io are free at 60 requests/min with no signup.

Which has better liquidity — Polymarket or Kalshi?

Both have grown substantially, but liquidity is market-specific and changes over time. A political election question on Polymarket and a Fed-rate question on Kalshi will have different depth profiles. Rather than cite figures that go stale quickly, check each platform's current top markets directly.