What Metaculus is, how it differs from a market, and its API

Metaculus is an online forecasting platform that collects probability forecasts and aggregates them; by its own account it is not a prediction market.

Metaculus has some similarities to a prediction market, but ultimately is not one.

Metaculus is an online forecasting platform and aggregation engine working to improve human reasoning and coordination on topics of global importance.

When we read it, the site counted 4,424,888 predictions on 25,700 questions, 13,057 of them resolved.

There is no money or share price: you enter a probability, and Metaculus combines everyone’s into a Community Prediction.

Metaculus, in contrast, directly solicits predicted probabilities from its users, then aggregates those probabilities.

For markets with real money, see Kalshi fees and Polymarket fees.

Yes. Metaculus has an official API documented at metaculus.com/api, and every request needs an account token.

All API requests require valid authentication credentials. Unauthenticated requests will be rejected with an authentication error.

What an ordinary account can see: Only on about 50 questions; an ordinary account gets question text and its own data.

The current value of the Community Prediction is available on a small set of ~50 questions.

Not without written permission: its terms bar using API data to train or evaluate AI or machine learning models.

In particular: data may not be used to train, evaluate, or otherwise create or develop AI/ML models or algorithms without Metaculus's prior written permission; and any commercial use whatsoever requires a separate written agreement.