TourneyRadar
Upcoming chess tournaments from 140+ national federations worldwide

Get and set activities, health data and more.
Tredict API is a free Sports & Fitness API that requires OAuth authentication, is served over HTTPS and has unconfirmed CORS support.
This guide enables you to authorize our users into your application via OAuth2 and upload their activities to our activity endpoint, download a list of activities or upload health data to the user's account. The endpoints described here also cover the Personal API.
Details from tredict.com.

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Upcoming chess tournaments from 140+ national federations worldwide
Real-time sports data: odds, scores, stats & prediction markets, 30+ leagues, 18+ sportsbooks
Query sports data, including teams, players, games, scores and statistics
The Tredict API is provided by Tredict (tredict.com). This guide enables you to authorize our users into your application via OAuth2 and upload their activities to our activity endpoint, download a list of activities or upload health data to the user's account. The endpoints described here also cover the Personal API.
Yes. The Tredict 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.
Yes. The Tredict API uses OAuth authentication, so you need to register for credentials before making requests.
CORS support for the Tredict API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The Tredict API is served over HTTPS, so it's safe to use in production.