research
pdata.world collects prices, volumes and results from eight prediction-market venues — Polymarket, Kalshi, Manifold, Myriad, Limitless, Predict, Opinion and Gemini — every 10 to 60 minutes. These reports use that record to answer questions the venues' own pages do not: whether the prices were right, what their numbers mean, and how the venues compare. Each is dated, says how it was measured, and says what it cannot show.
Reports
- How accurate were prediction-market prices a day before the result?
Prices 24 hours and 7 days before close, checked against the outcome each venue reported, for tens of thousands of settled markets on Polymarket and Kalshi.
Updated 7 October 2026.
- How eight prediction-market venues count volume
Shares, contracts, play money or dollars: what the volume figure means on Polymarket, Kalshi, Manifold, Myriad, Limitless, Predict, Opinion and Gemini, and the traps in each.
Updated 7 October 2026.
- What each prediction-market API gives you
Authentication, pagination, rate limits, prices, volume and settlement data across eight venue APIs, from running an integration against all of them.
Updated 7 October 2026.
- Same question, different price: prediction markets across venues
Pairs of markets asking the same question on two venues, read by hand, with the price each showed at the same hour and why the large gaps were large.
Updated 7 October 2026.
- What eight prediction-market venues list, by category
Open events, open markets and the split of each venue's 24-hour volume by category, counted from pdata's database, with what the counts leave out.
Updated 7 October 2026.
The data behind them
The same data is open to everyone: the API, nightly bulk files, a public read-only Postgres connection and an MCP server for AI assistants, all described on the data page. It is published under CC BY 4.0: use it, and cite pdata.world.