Sports model win probabilities and fair odds across 13 leagues.
Bet Better API is a free Sports & Fitness API that requires no API key, is served over HTTPS and supports CORS, so it can be called from the browser.
A free, open, no-key JSON API of sports betting model win probabilities and fair odds across 13 sports. CC BY 4.0 licensed. Documentation, endpoints and examples.
Details from betbetter.world.

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The Bet Better API is provided by BetBetter (betbetter.world). A free, open, no-key JSON API of sports betting model win probabilities and fair odds across 13 sports. CC BY 4.0 licensed. Documentation, endpoints and examples.
Yes. The Bet Better API is listed in the Sports & Fitness category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
No. The Bet Better API requires no authentication, so you can start making requests without signing up.
Yes. The Bet Better API supports CORS, so front-end JavaScript can call it directly.
Yes. The Bet Better API is served over HTTPS, so it's safe to use in production.