Kalshi API: Sports Contract Prices in Your App

Yes. Kalshi publishes the Kalshi Exchange API, with REST, WebSocket and FIX access, OpenAPI specs and official Python SDKs. If you searched for a Kalshi odds API, this is the official source, and reading prices costs nothing: the market data endpoints for series, events, markets and the order book need no key.

Trading needs a key. Any Kalshi member can create one under API Keys in Profile Settings, and the docs name no approval step. You sign each request with an Ed25519 key (the default since 1 October 2026) or an RSA key, and Kalshi never stores your private key. The WebSocket asks for a signed key at the handshake, even for public channels such as the order book and the ticker.

Rate limits are token budgets per second. Most requests cost 10 tokens. A Basic account starts with 200 read and 100 write tokens per second, and Kalshi raises the budget as your trading volume grows. A demo exchange with mock funds and its own keys lets you test orders first. Its prices do not track the real market, so test your code there and keep your model on production data.

Using the API means you accept Kalshi's Developer Agreement, so read it before you write code. The full docs live at docs.kalshi.com.

Kalshi's licence draws the line for you. The Developer Agreement limits the API to a member's own trading on Kalshi. It bars collecting, caching, aggregating or storing API data for any other use, and bars sharing that data with third parties without Kalshi's written authorization. Everything the official API allows is about your own account.

So use Kalshi's API when you trade on Kalshi. Order placement, your fills and positions, RFQs (requests for quote) and the full bid book at every price come from there and nowhere else. A trading bot, a market-making script or a private model that trades your account belongs on the official API, and free reads make it the cheapest data you will find for that job.

Use an aggregated feed when other people will see Kalshi prices, or when Kalshi is one price among many. Your own key does not cover a public product, so you need written consent from Kalshi or a feed whose terms cover display. Ask the odds API how it sources Kalshi and what its terms let you show before you ship. A feed also maps Kalshi markets onto the same games as DraftKings, FanDuel and the other books it carries, in one schema behind one key and one rate limit. Doing that yourself means matching Kalshi's series and event ids to every sportsbook's ids, every season, as our betting exchange API guide describes.

Our take: trade through Kalshi's API, compare and display through a feed. The table below lists each odds API in our directory that carries Kalshi, with the source and date of each claim, and the Coverage Map filters them further by league and market.

Kalshi lists sports as event contracts with a YES and a NO side. The price is in dollars per contract, and a winning contract pays $1, so a YES price of $0.62 means a 62% implied chance. That works out to about -163 in American odds before fees. The API returns fixed-point dollar strings next to older integer-cent fields, so pick one and use it everywhere in your parser.

• Game contracts and props. Contracts on game outcomes, plus NFL player props on passing, receiving and rushing yards and touchdowns since October 2025. Our player props API guide covers how feeds structure those markets.
• Combos. Multi-leg contracts, with football combos on their own series. Combos of independent NFL legs created after 19 August 2026 carry no maker fee.
• The order book. Full bid depth at each price over REST, WebSocket deltas and a FIX market data session. Kalshi returns bids only, because a YES bid at one price is a NO ask at the reciprocal price.
• Trades and your account. The trade tape and the ticker for every market, plus your own orders, fills and positions with a key.

Sports carry the exchange. A Pew Research Center study found that sports drove 80% of Kalshi volume from July 2024 through April 2026, and Kalshi's lifetime volume passed $100 billion by mid-June 2026. The API also serves non-sports markets and a separate Perps line for crypto futures, so filter by series before you treat a market as a game.

Kalshi sets no line. Traders set the price on an order book, and Kalshi earns trading fees on fills. Put a Kalshi price next to a sportsbook line and you see two kinds of market on one game: traders who face each other, and a book that posts a number and takes the other side.

The gaps carry information. When Kalshi and the books disagree, one of them moves, and the one that moves first tells you where the money came in. A Kalshi price on a busy market also gives you a second fair-price check for sportsbook odds, next to sharp books such as Pinnacle and Circa. When all three agree and a soft book does not, you have found a line worth a closer look.

Two checks keep the comparison honest. Subtract Kalshi's fee before you call its price better than a book's, because the raw contract price overstates your return. And look at the size: a price with little money behind it says less than the same price on a deep book. A feed may flatten Kalshi into one best price, so ask for a sample payload if size matters to your model.

• Price comparison. Show Kalshi next to sportsbook lines, converted to odds and net of fees. Add Novig and ProphetX for two more US exchanges.
• Divergence alerts. Flag games where Kalshi and the sportsbook consensus differ by more than the fees, and log how fast the gap closes.
• Closing line value. Grade your picks against the Kalshi close next to the sportsbook close. A historical odds feed that stores Kalshi saves you from building the archive.
• Prop research. Line up Kalshi's NFL yardage and touchdown contracts against the same props at the books.
• Trading bots. Quote or take on Kalshi through the official API, with an aggregated feed as your outside reference price.

Kalshi is regulated by the CFTC as a designated contract market, but states contest its sports contracts. They are not live in Nevada, and courts have paused or blocked them in Michigan and Massachusetts. Utah sued Kalshi in state court in October 2026 to stop its sports contracts there. Check where your users are before you build a product around Kalshi prices.

The website has its own terms. Kalshi's Data Terms of Use limit the prices on kalshi.com to personal, non-commercial use and ban redistribution without written authorization. Kalshi does license its data by contract to media partners such as CNN and CNBC, so a written deal is possible if your product needs one.

New to odds data? Start with our getting started guide, and try the free odds APIs for a first prototype.