What Is a Prediction Market API?

A prediction market API provides programmatic access to real-time event probability data aggregated from multiple prediction markets — letting developers build tools that reason about future outcomes.

The short answer

A prediction market is a platform where participants buy and sell contracts on the outcome of future events. The price of a contract reflects the crowd's collective probability estimate for that outcome — for example, a 63-cent contract represents a 63% implied probability.

A prediction market API sits between those markets and your code. Instead of scraping prices from individual platforms, you call one endpoint and receive a structured probability estimate, often aggregated across multiple markets for higher reliability.

What data is available

Most prediction market APIs return some combination of the following fields per event:

Event title — a human-readable description of the outcome being traded
Consensus probability — aggregated probability from one or more markets
Confidence score — how much markets agree with each other
Market count — how many independent markets contributed to this estimate
Spread / divergence — the range between highest and lowest market estimate
Resolution date — when the event will resolve

The Meridian Edge API also returns a divergence_pct field that flags when markets disagree by more than 3%. This is useful for identifying potential mispricings or breaking-news situations before consensus catches up.

Common use cases

Research and analytics

Researchers use prediction market data as an alternative to polling or expert forecasting. The data is updated continuously and reflects new information faster than surveys.

Research and analysis tools

Developers build tools that monitor divergence between markets and alert when cross-market spreads exceed a threshold. The API makes polling many events at scale practical.

News and media applications

Publishers embed real-time probability widgets or build "likelihood meters" for ongoing events — election coverage, championship consensus, or economic indicator forecasts.

AI and LLM grounding

Language model applications use prediction market consensus to ground claims about future outcomes with calibrated probabilities rather than stale training data.

How to authenticate

The Meridian Edge API uses API key authentication via the X-API-Key header:

curl -H "X-API-Key: me_free_your_key" \
  "https://meridianedge.io/api/v1/consensus?sport=NBA&limit=5"

Starter keys allow 1,000 calls per day ($29/mo). Pro keys allow 10,000 calls per day ($99/mo).

Frequently asked questions

What is a prediction market API?

A prediction market API is a web service that provides programmatic access to probability data from prediction markets. Developers use it to retrieve real-time event probabilities, consensus scores, and divergence signals for events like sports games, economic outcomes, and political events.

What data does a prediction market API return?

Typical endpoints return event titles, current probability estimates, confidence scores, number of contributing markets, and spread metrics. Some APIs — like Meridian Edge — also return divergence signals when different markets disagree significantly on the same event.

Is there a free prediction market API?

Yes. Meridian Edge offers a starter tier with 100 API calls per day. Instant activation is required. You can get a key instantly at meridianedge.iothe pricing page.

Try the API — included

Plans start at $29/mo. 1,000 calls/day. Key in 10 seconds.

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