Does Polymarket have a public API, and is it free?

Yes. Polymarket publishes its own API (REST, WebSocket, GraphQL). Reading public market data is free and needs no API key. Its rate limits and sign-in methods are in the table on this page.

Does Kalshi have a public API, and is it free?

Yes. Kalshi publishes its own API (REST, WebSocket, MCP). Reading public market data is free and needs no API key. Its rate limits and sign-in methods are in the table on this page.

Where can I get historical prediction market data?

42 of the APIs here offer historical data, but only 5 state an exact start date; the earliest is Probalytics, from 2 October 2020. Use the "Historical data" filter to see them all.

Which prediction market data providers have a free tier?

27 of the independent providers state a free tier or free use: 0xArchive, Adanos Software, Adjacent, Bravado, DepthFeed, KalshiSpy and 21 more. Limits differ; each row gives them.

How much does prediction market data cost?

The cheapest published plans range from $10 a month (outcometick) to $200 a month (Prediction Labs). What each plan includes differs, so compare the data and history columns too.

Which prediction market APIs work with AI agents?

24 offer an MCP server that AI assistants can call directly: Kalshi, Limitless, Hunch, 0xArchive, Adjacent, Bravado and 18 more.

Prediction market APIs compared

The markets' own APIs, the data providers built on top of them and the open-source clients, side by side: what data each one gives, how far back it goes, how it is delivered and what it costs. Every fact comes from the provider's own documentation, pricing page or repository, read on 6 November 2026.

markets with their own API: 26; markets with their own API
independent data providers: 42; independent data providers
with a free tier: 41; with a free tier
with historical data: 42; with historical data

MarketAny Polymarket 56 Kalshi 33 Limitless 10 Predict.fun 9 Opinion 8 Hyperliquid 5 Myriad 5 Manifold 4 Novig 4

NeedsAnything Free tier Historical data WebSocket MCP for AI agents Places orders Bulk files

8 APIs match. Show all

The markets' own APIs

Run by the exchange itself. Usually free to read, with a key or a wallet signature to trade. Open a row for sign-in, rate limits and links.

Official prediction market APIs
Market	Prices	Order books	Trades	History	Wallets	Trading	Delivery	Free	Paid from	Details
Opinion	Prices: yes	Order books: yes	Trades: yes	History: yes	Wallets: yes	Trading: yes	RESTWebSocket	Yes	–
Data Markets Prices Order books Trades Price history Wallets Resolutions Trading Delivery REST WebSocket SDKs: Python, TypeScript Markets covered Opinion Sign-in none for public OpenAPI data; API key for private endpoints/WebSocket; wallet signature to create key and authorize trading Free use Yes. Public data 5 requests/second/IP; authenticated 15 requests/second/API consumer. No paid API tariff stated. Rate limits Public 5 requests/second/IP; authenticated 15 requests/second/API consumer. Separate rate-limit page only states 15/second. Cheapest paid plan Not stated History from Not stated Links DocumentationChecked 6 November 2026

Data providers

Independent services that collect, clean and resell market data, often across several exchanges and further back than the exchanges keep. Open a row for what each plan includes.

Prediction market data providers
Provider	Prices	Order books	Trades	History	Wallets	Trading	Delivery	Free	Paid from
PredexonPolymarket, Kalshi +3	Prices: yes	Order books: yes	Trades: yes	History: yeswith books	Wallets: yes	Trading: not stated	RESTWebSocketMCPFiles	Yes	$49 a month
Data Markets Prices Order books Trades Price history Order-book history Wallets Resolutions Signals Delivery REST WebSocket MCP bulk files (Parquet) Markets covered Polymarket, Kalshi, Opinion, Limitless, Predict.fun Sign-in API key (x-api-key) Free use Yes. 1 request/second; 1,000 premium requests/month; free/historical endpoints unlimited by monthly quota, still rate-limited. No free WebSocket. Tick downloads billed separately; $50 credits conditional on adding payment method. Rate limits Free 1; Dev 20; Pro 100 requests/second; Enterprise custom. Cheapest paid plan $49 a month. Dev: 20 requests/second, 1M premium requests/month, Smart Money and Binance references, 10 WebSocket subscriptions × 10 items; overage $5/100,000 premium calls. History from Not stated Links Documentation PricingChecked 6 November 2026
PredictefyPolymarket, Polymarket US +14	Prices: yes	Order books: yes	Trades: yes	History: yes	Wallets: yes	Trading: yes	RESTWebSocketMCPSQL	Yes	$48.88 a month
Data Markets Prices Order books Trades Price history Wallets Resolutions Signals Trading Delivery REST WebSocket MCP SQL SDKs: TypeScript, Python Markets covered Polymarket, Polymarket US, Kalshi, Hyperliquid, Limitless, Opinion, Predict.fun, Myriad, Rain, Gemini, SX Bet, PRED, Pascal, XO, PredictStreet, Novig Sign-in API key; trading also uses client-side venue/wallet signing Free use Yes. 25,000 weighted credits/month; 60 requests/minute; 1 key; 2 live streams; 7-day history window; paper trading up to 10 open orders. Rate limits Free 60; Builder 300; Pro 3,000 requests/minute; Enterprise custom. Cheapest paid plan $48.88 a month. Builder: 250,000 credits/month, 300 requests/minute, 3 keys, 20 streams, 12-month history entitlement, bulk endpoints; no replay. $11/100,000 credit top-ups; annual advertises 20% off. History from Not stated Links Documentation PricingChecked 6 November 2026
pdataPolymarket, Kalshi +6	Prices: yes	Order books: not stated	Trades: not stated	History: yes	Wallets: not stated	Trading: not stated	RESTMCP	Yes	–
Data Markets Prices Price history Signals Delivery REST MCP Markets covered Polymarket, Kalshi, Manifold, Myriad, Limitless, Predict.fun, Opinion, Gemini Sign-in none Free use Yes. OpenAPI states all endpoints public, no auth and no rate cards. Numeric rate limit not stated. Rate limits Not stated Cheapest paid plan Not stated History from Not stated Links DocumentationChecked 6 November 2026
UnifAIPolymarket, Opinion	Prices: yes	Order books: not stated	Trades: not stated	History: not stated	Wallets: yes	Trading: yes	MCP	?	–
Data Markets Prices Wallets Trading Delivery MCP SDKs: JavaScript, TypeScript, Python, Rust Markets covered Polymarket, Opinion Sign-in Agent API key; separate Toolkit API key for toolkit hosting; connected-wallet authority for execution Free use Not stated Rate limits Not stated Cheapest paid plan Not stated History from Not stated Links DocumentationChecked 6 November 2026

Open-source clients

Code libraries for calling the markets' APIs, with the language, licence and latest release from each repository.

CCXT prediction market exchanges
JavaScript, TypeScript, Python, C#, PHP, Go, Java, Rust for Binance, Hyperliquid, Kalshi, Limitless, Myriad, Opinion, Polymarket, Predict.fun, SX Bet
MIT, released 4 November 2026
dr-manhattan
Python for Polymarket, Kalshi, Opinion, Limitless, Predict.fun
released 7 December 2025
PMXT
Python, TypeScript for Polymarket, Polymarket US, Kalshi, Limitless, Probable, Baozi, Myriad, Opinion, Metaculus, Smarkets, Hyperliquid, Gemini Titan, SuiBets, Rain, Hunch
MIT, released 18 July 2026

Quick answers

Does Polymarket have a public API, and is it free?: Yes. Polymarket publishes its own API (REST, WebSocket, GraphQL). Reading public market data is free and needs no API key. Its rate limits and sign-in methods are in the table on this page.
Does Kalshi have a public API, and is it free?: Yes. Kalshi publishes its own API (REST, WebSocket, MCP). Reading public market data is free and needs no API key. Its rate limits and sign-in methods are in the table on this page.
Where can I get historical prediction market data?: 42 of the APIs here offer historical data, but only 5 state an exact start date; the earliest is Probalytics, from 2 October 2020. Use the "Historical data" filter to see them all.
Which prediction market data providers have a free tier?: 27 of the independent providers state a free tier or free use: 0xArchive, Adanos Software, Adjacent, Bravado, DepthFeed, KalshiSpy and 21 more. Limits differ; each row gives them.
How much does prediction market data cost?: The cheapest published plans range from $10 a month (outcometick) to $200 a month (Prediction Labs). What each plan includes differs, so compare the data and history columns too.
Which prediction market APIs work with AI agents?: 24 offer an MCP server that AI assistants can call directly: Kalshi, Limitless, Hunch, 0xArchive, Adjacent, Bravado and 18 more.

Nobody pays to be listed or for their position. A tick means the provider's own pages say it offers that data; a dash means they do not say. Using or reselling a market's data is governed by that market's own terms, whoever supplies it. Prices and limits change, so the provider's own page is the one that counts. Missing an API? Add it for free, or browse every data feed and API in the directory.

Every profile is built from the product's own pages, and Vultax keeps a dated copy of each one. How the directory is made. Companies already listed can manage their profile.