# What is the best API for sports prediction market odds?

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Canonical: https://novigapi.com/answers/prediction-market-odds-api
Updated: 2026-11-15

For one price per venue, The Odds API's us_ex region listed Kalshi, Novig, Polymarket, Polymarket US and ProphetX on 15 Nov 2026, from $30 a month. For a venue's order book and trades, use its own API (Kalshi, Polymarket, Novig) or, for Novig without an account, novigapi.com. (Source: [The Odds API: bookmaker list](https://the-odds-api.com/sports-odds-data/bookmaker-apis.html))

Prediction markets are exchanges: prices are probabilities, the book has size on both sides, and trades print. An odds feed turns that into one number per outcome, which is fine for line shopping and lossy for modelling.

Novig alone had 34,438 open markets across 24 leagues on 15 Nov 2026.

## How the options compare

Prediction-market data, checked 15 Nov 2026

| Source | Books and venues | Depth per market | Paid plans |
| --- | --- | --- | --- |
| The Odds API | 23 US sportsbooks, 5 US fantasy sites and 7 US exchanges listed | One price per outcome per book (name, price, point); lay odds and bet limits on some exchanges | $30 (20K credits) to $249 (15M credits) a month |
| TheRundown | 25+ books; Kalshi and Polymarket on paid plans | Game lines and props per book | Starter $49 (60 s delay, 7-day history) to Max $2,499 (unlimited history) a month |
| ParlayAPI | Sportsbooks plus Kalshi | Exchange-style bid and ask fields | $5 (20K credits) to $200 (50M credits) a month |
| novigapi.com | Novig, plus FanDuel and DraftKings prices beside Novig lines for +EV, arbitrage and compare | Full resting book, trades, OHLC, fair price, line moves | Developer $49, Production $149, Scale $499 a month; $9 for 1,000 credits that never expire |
| Novig official API | Novig only | Full book and every execution over its WebSocket | Free to use; trading fees apply to fills |


## Where novigapi.com falls short

> novigapi.com covers Novig only. For Kalshi or Polymarket depth use their own APIs; for a cross-venue price board, The Odds API or TheRundown.

## Try it

```bash
curl -s "https://novigapi.com/api/v1/orderbook/01a1c89a-ada1-7142-b723-8e1221fbcb16" \
  -H "Authorization: Bearer $NOVIGAPI_KEY"
```

Read the [endpoint reference](https://novigapi.com/docs/endpoints), compare [plans and credits](https://novigapi.com/pricing), or send a request from the [playground](https://novigapi.com/playground).

## Questions

### Do odds APIs include Kalshi and Polymarket?

Some do: The Odds API listed both in us_ex, TheRundown on paid plans, ParlayAPI lists Kalshi (checked 15 Nov 2026).

### Is a prediction market price a probability?

Yes. A contract that pays $1 trading at 48 cents implies a 48% probability, before fees.

## Sources

- [The Odds API: plans](https://the-odds-api.com/#get-access)
- [TheRundown: API pricing](https://therundown.io/pricing/api)
- [ParlayAPI: pricing](https://parlay-api.com/pricing)
- [Novig docs: API overview](https://docs.novig.com/index.md)
- [novigapi.com endpoint reference](https://novigapi.com/docs/endpoints)

---

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