about pdata
pdata (pdata.world) aggregates over 400,000 open prediction markets (October 2026) from 8 platforms — Polymarket, Kalshi, Manifold, Myriad, Limitless, Predict, Opinion and Gemini — into one read-only website and API. It is free, needs no signup, and takes no trades.
Every number on pdata comes from a platform's own public API. Probabilities and volume are passed through as each platform reports them; 24-hour moves are computed from pdata's own snapshots. The exact pipeline is on the methodology page.
the 8 platforms
- Polymarket is an onchain prediction market on Polygon, trading in pUSD, a stablecoin backed 1:1 by USDC.
- Kalshi is a CFTC-designated contract market for event contracts in US dollars; each contract settles at $1 or $0.
- Manifold runs play-money prediction markets in mana, which cannot be converted to cash.
- Myriad runs onchain prediction markets on Abstract and BNB Chain in stablecoins; pdata leaves out its points markets.
- Limitless is a prediction market on Base whose YES and NO shares are fully collateralised by USDC.
- Predict (predict.fun) is a prediction market on BNB Chain with USDT collateral.
- Opinion (opinion.trade) is an onchain prediction exchange on BNB Chain with USDT collateral.
- Gemini lists event contracts as Gemini Predictions, on Gemini Titan, a CFTC-designated contract market, in US dollars.
how fresh it is
pdata polls each platform on its own cadence, waiting 10 to 60 minutes between cycles depending on the source. When a market's price or volume has changed, it records a snapshot, at most once every 30 minutes per market, and derives the 24-hour probability changes and the biggest-movers lists from those snapshots. The news page refreshes after each Polymarket ingest cycle, typically every 15 to 20 minutes.
matching markets across platforms
Once a night, pdata embeds every open event title with the mxbai-embed-large-v1 model and links each event to its nearest neighbours. Two events on different platforms are marked as the same question when their titles score at least 0.85 cosine similarity, their end dates fall within 3 days of each other, and their titles do not name conflicting years or thresholds. Sports and asset-price markets are left out. A match is a similarity judgement, not a guarantee, so pdata shows the other market's own title next to it.
ways to get the data
The same data is available five ways: this website; a public REST API at api.pdata.world, described by its OpenAPI documentation; an MCP server for AI assistants at api.pdata.world/mcp, with 14 read-only tools; a public read-only Postgres database; and nightly bulk files at api.pdata.world/bulk/. The agent guide has the connection details for each. None of them needs a key.
pdata's aggregation is published under CC BY 4.0. Each platform's own terms apply to its data. Details are on the data access page.
what pdata does not do
pdata does not trade, take orders, hold funds, run accounts or carry referral links. It does not convert units between platforms: Polymarket counts shares and Kalshi counts contracts, each paying $1 at resolution, while Manifold counts play-money mana. It does not merge a question listed on two platforms into one row; each platform's market stays its own. The homepage's in-focus grid is chosen by a score of 24-hour move times volume, with one hand-maintained exception: a short title blocklist that removes engagement-bait formats.