About Best Prediction Market APIs

Best Prediction Market APIs is a directory of 30 prediction market APIs for Polymarket and Kalshi traders, with one page per API and a category hub for each job.

The team behind Kairos (kairos.trade), a cross-venue trading terminal, builds and runs this site. We say so on every page. Kairos takes the terminal slot in each list because cross-venue aggregation is the one job a single-venue API cannot do. Every other API is presented on its own merits.

How a page gets written

Each API page is built from the API's own site, documentation or repository, read on the date shown at the top of the page. Prices are quoted as displayed on the live pricing page. Venue coverage is what the API itself claims. GitHub stars and last-push dates come from the GitHub API. A fact we could not confirm on a primary source is left out rather than guessed.

Pages carry a last-checked date and are re-read when the site is rebuilt. If a API has changed its pricing or shut down, the live site wins and this page is behind.

What this site is not

Nothing here is financial, legal or tax advice. Event contracts and prediction markets carry real market risk, and a API that finds an edge does not remove it. Read each venue's rules before you trade.

The network

Best Prediction Market APIs is one of three guides: best prediction market Tools and best prediction market Bots cover the other two jobs.

Contact

Corrections and additions: open an issue with the URL of the API and what changed, or write to the Kairos team through kairos.trade.