# Prediction Markets API | Unified API
URL: https://sockodds.com/prediction-market-api/

> Real-time Kalshi and Polymarket prices alongside Australian sportsbook odds in one unified API.

Kalshi and Polymarket contract prices, the Betfair Exchange and ProphetX, alongside every Australian sportsbook — one schema, one `byBookmaker` object, keyed by `bookmakerID`.

## Why combine prediction markets with sportsbook odds?

A prediction market price is a probability with very little margin in it. Next to a bookmaker's price on the same outcome it is the cleanest edge signal there is — and until now it lived in a different API with a different schema. SockOdds normalises the contract into the same `oddID` as the sportsbook market, so `polymarket` and `sportsbet` are two keys in the same object.

## Covered prediction market platforms

| Platform | bookmakerID | Type | Events priced | Leagues |
| --- | --- | --- | --- | --- |
| [Betfair Exchange](https://sockodds.com/bookmakers/betfairexchange-odds-api/) | `betfairexchange` | Betting exchange | 164 | AFL, AFLW, ATP, Bundesliga, Premier League, Ligue 1, IPL, Serie A, La Liga, MLB, MLS, NFL, NRLW, Rugby Union Internationals, Champions League, WTA |
| [Kalshi](https://sockodds.com/bookmakers/kalshi-odds-api/) | `kalshi` | Prediction market | 253 | ATP, Bundesliga, Premier League, Ligue 1, Serie A, La Liga, MLB, MLS, NFL, WTA |
| [Polymarket](https://sockodds.com/bookmakers/polymarket-odds-api/) | `polymarket` | Prediction market | 292 | ATP, Bundesliga, Premier League, Ligue 1, La Liga, MLB, MLS, NFL, WTA |
| [ProphetX](https://sockodds.com/bookmakers/prophetexchange-odds-api/) | `prophetexchange` | Betting exchange | 187 | Bundesliga, Premier League, Ligue 1, Serie A, La Liga, MLB, MLS, NFL |

## What can you build with a prediction markets API?

### Arbitrage and cross-market analysis tools

Scan a contract price against every book's price on the same outcome; see the [prediction market arbitrage](https://sockodds.com/use-cases/prediction-market-arbitrage-api/) use case.

### Research and forecasting platforms

Use exchange and contract prices as a low-margin probability benchmark for models.

### Odds aggregators and comparison sites

Show Polymarket next to Sportsbet in the same row without a second integration.

### Algorithmic trading systems

Diff contract prices against book prices every refresh and act on the divergence.

### Sports media and content products

"The market thinks" widgets with a real market behind them.

### AI and ML models

Fair-price labels for training, with `fairOdds` derived from exactly these sources.

## Why SockOdds for prediction market data?

### One API, every market type

Sportsbooks, exchanges and prediction markets in one response.

### No blockchain complexity

Polymarket is a price in a JSON object, not an on-chain query.

### Already normalised with sportsbook data

Same `oddID`, same envelope, same American string plus decimal.

### Same refresh, same flags

Every ~2 minutes with `available` and `lastUpdatedAt` per entry.

### Retained history

Finished events stay in the feed for backtesting.

## Example request

```bash
curl "https://api.sockodds.com/v2/events/?leagueID=NFL&bookmakerID=polymarket,kalshi,sportsbet&oddID=points-home-game-ml-home&includeOpposingOdds=true&limit=1" \
  -H "x-api-key: YOUR_API_KEY"
```

## Frequently asked questions

### What is a prediction markets API?

A feed of contract prices from prediction markets, normalised so they can be compared with bookmaker odds. In SockOdds they are part of the same events feed.

### Which prediction markets do you cover?

Betfair Exchange, Kalshi, Polymarket, ProphetX.

### How often is the prediction data updated?

Every ~2 minutes, the same cadence as the sportsbooks.

### Is there a free trial for the prediction market API?

Prediction-market prices are on Base and above; the free Lite plan covers the Australian books on AFL and NRL.

## Start building today

Free plan available. Set up in 5 minutes. Scale when you're ready.