Previa aggregates market data from multiple prediction market platforms into a single interface. Each platform has different data availability and connection options.
Kalshi
Kalshi is a US-regulated prediction market exchange (CFTC-regulated). Markets cover politics, economics, weather, tech, sports, and more.
What Previa pulls from Kalshi:
- Live event and market listings with full metadata
- Real-time YES/NO prices
- 24-hour volume and liquidity
- Historical OHLCV price data (candlesticks)
- Market resolution status and outcome data
- Series and event groupings (markets organized into events)
Data freshness: Kalshi data is polled continuously. Prices and volume figures update whenever the poller fetches new data from the Kalshi Trade API.
Portfolio tracking: Connect your Kalshi account using your API key and secret to track open positions and P&L. Available on Pro and Enterprise plans.
Polymarket
Polymarket is a decentralized prediction market built on Polygon (an Ethereum Layer 2 network). It is one of the largest prediction markets by volume.
What Previa pulls from Polymarket:
- Live event and market listings with full metadata
- Real-time YES/NO prices via the Central Limit Order Book (CLOB) API
- 24-hour volume and liquidity from the Gamma and Data APIs
- Historical price data (OHLCV candlesticks)
- On-chain condition IDs for independent verification
Data freshness: Polymarket data is fetched from three separate APIs (Gamma, Data, and CLOB) and merged into a single normalized record per market.
On-chain verification: Every Polymarket market has a condition ID — a contract address on the Polygon blockchain. From any market’s detail page, click View on Polygonscan to inspect the contract directly.
Portfolio tracking: Connect your Polymarket wallet address to track positions. Available on Pro and Enterprise plans.
Polymarket portfolio tracking reads positions from the public CLOB API using your wallet address. Full on-chain USDC balance reads are on the roadmap.
Data normalization
Previa normalizes data from both platforms into a common format:
| Field | Kalshi source | Polymarket source |
|---|
| YES price | yes_ask from Trade API | Best ask from CLOB |
| NO price | no_ask from Trade API | Derived from YES price |
| Volume 24h | volume (24h window) | volumeNum from Gamma API |
| Liquidity | open_interest | liquidityNum from Gamma API |
| Expires | close_time | endDateIso |
Coming soon
Additional platforms are planned for future releases:
| Platform | Type | Status |
|---|
| Metaculus | Community forecasting | Planned |
| Manifold | Play-money prediction market | Planned |
| PredictIt | Political prediction market | Planned |
