Prediction Market APIs Compared (2026): Kalshi, Polymarket & More

Which prediction market API should you build on? For political, economic and other real-money markets, the main public APIs are Kalshi’s and Polymarket’s; Novig has one for sports, and Manifold offers a free play-money API. This page compares them side by side and links to our full guide for each, checked October 2026.

The APIs compared

	Kalshi	Polymarket	Novig	Manifold
Markets	Politics, economics, sports, culture and more	Politics, crypto, sports, culture and more	Sports only	Anything users create
Money	USD	Crypto (main exchange)	USD	Play money
Reading prices	No account needed	No account needed	Signed key (one small public route)	No key needed
Trading auth	Signed API key	L2 credentials + wallet signature	Ed25519 or P-256 signed key	`Authorization: Key` header
Guide	Kalshi API	Polymarket API	Novig API	Manifold API

For political markets

Kalshi and Polymarket carry the deepest election and policy markets. Both let you read events, markets and prices without an account, which is all you need for dashboards and research:

curl "https://external-api.kalshi.com/trade-api/v2/events?status=open&limit=5"
curl "https://gamma-api.polymarket.com/events?active=true&closed=false&limit=5"

Our live boards, such as politics markets and the price-gap scanner, are built on these same public endpoints. Matching the same question across the two venues is the hard part: names, outcome labels and settlement rules differ, so check each market’s rules before you compare prices.

For sports

Kalshi and Polymarket both list sports. Novig is sports-only, with a paper environment that’s handy for testing a bot without real money, but its signed routes are blocked from Arizona, Michigan and Nevada and from VPNs.

For practice and research

Manifold is free, has the fewest hoops (500 requests a minute per IP, no key to read) and lets you create and resolve your own markets. It’s play money, so prices aren’t backed by real stakes.

What about PredictIt?

Community libraries use a PredictIt market-data feed, but we couldn’t load it or PredictIt’s terms when we checked, so we haven’t covered it here. If you use it, read PredictIt’s terms first.

FAQ

Is there a free prediction market API?

Yes. Kalshi, Polymarket and Manifold all let you read market data free without an account.

Which API is best for election odds?

Kalshi and Polymarket, which carry the largest political markets. Use both if you want to compare venues.