Which prediction-market API should I use?
The short version of the question, stripped of context: you need programmatic access to Kalshi and/or Polymarket pricing, and you're deciding whether to integrate the venues directly or use something that sits on top of them. Here's the technical case for seven real options, evaluated on auth complexity, rate limits, and what you actually get for the integration cost. Sourced from each provider's own docs as of 2026-07-09.
Auth model is the first filter
Kalshi's own API uses RSA-PSS request signing. Polymarket's uses a two-layer EIP-712 wallet signature plus HMAC, and every order needs its own EIP-712 signature on top of that. If you don't want to implement either of those, that's the entire reason aggregators exist. dino.markets and Tatum both reduce this to a single Bearer API key or key pair, no wallet or signing scheme required to read data. PolyRouter and Prediction Hunt do the same. PMXT is the exception worth flagging: because it actually places orders, it still needs your real credentials for the venue it's executing on.
dino.markets
Single Bearer key. Sports-only scope: matches Kalshi and Polymarket games, returns an entity-confidence and resolution-confidence score per match, plus an explicit settlement-risk flag. Free tier is a flat 60 requests a minute, no monthly credit pool, no card required. WebSocket push starts on Basic. Native MCP server ships on every tier including Free. Limitation worth stating plainly: no politics, crypto, or culture markets, only sports. Pricing on our pricing page: $0 Free, $60/mo Basic, $200/mo Pro.
Tatum
One API key, one base URL, 38 endpoints across both Polymarket and Kalshi, built by an established crypto-infrastructure provider rather than a prediction-market-only startup. Prediction-market-specific pricing wasn't broken out on Tatum's public pricing page as of this writing, so budget for a sales conversation if you need a number. tatum.io
FinFeedAPI
Order-book snapshots, trades and quotes, and OHLCV history across Polymarket, Kalshi, Myriad, and Manifold, in one consistent response format, built on the same infrastructure as CoinAPI. Enterprise pricing only, no public rate card. If you already run on CoinAPI's infrastructure elsewhere, this is the path of least resistance. finfeedapi.com
PolyRouter
The widest venue coverage here: Polymarket, Kalshi, Manifold, Limitless, ProphetX, Novig, and SX.bet through one API. It ships its own MCP integration. Free tier caps at 10 requests a minute and the product is still in open beta as of 2026-07-09, worth weighing if you need production stability today. polyrouter.io
Prediction Hunt
Covers multiple platforms including Kalshi and Polymarket, and was built specifically to fill the integration gap Polymarket's acquisition of Dome left. Free tier needs no credit card and no Web3 wallet to read data, which lowers the integration floor considerably versus going direct to either venue. predictionhunt.com
Oddpool
If your integration needs extend beyond sports, Oddpool covers politics, crypto, economics, and culture alongside sports, plus whale-trade tracking at the $500+ level, across 700K+ markets. We found no MCP integration in its published docs. Full comparison · oddpool.com
PMXT
The only option here that executes trades, going beyond reading data: limit orders, balance checks, open-order management across Polymarket, Kalshi, and more, open-source and self-hostable if you want full control over infrastructure. Launched January 2026, so weigh that against the rest of this list's maturity. pmxt.dev
The decision tree, condensed
Need order execution beyond data: PMXT. Need five-plus platforms and can tolerate open-beta risk: PolyRouter. Need multi-platform with a card-free free tier: Prediction Hunt. Need categories beyond sports: Oddpool. Already on CoinAPI infrastructure: FinFeedAPI. Want the simplest possible two-venue integration with matcher confidence and MCP included: dino.markets.
Common questions
What's the actual integration decision here?
Auth complexity and venue count, mostly. If you only need Kalshi and Polymarket and want the simplest integration, dino.markets or Tatum are single-key setups. If you need five-plus platforms, Prediction Hunt or PolyRouter cost you more integration surface for that breadth.
Which of these can actually place orders, beyond reading prices?
PMXT, and only PMXT. Everything else on this list, including dino.markets, is a read-only data layer: you still hold your own account or wallet on the venue itself and place trades there.
Is any of this sourced from real Stack Overflow answers?
We looked directly and found almost no indexed discussion for this specific integration question; it's a narrow, recent developer niche. What follows is our own technical assessment rather than a summary of someone else's answer, and it's labeled as such.
Read the less technical version at best-prediction-market-api-reddit, the full comparison hub at /comparison, or our writing on Kalshi/Polymarket pricing at /blog. Start free at dino.markets/login.