Balldontlie provides access to stats data from the NBA.
balldontlie 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.
Real-time stats for NBA, NFL, MLB, NHL, Soccer, Tennis, Golf, Esports & 20+ leagues. Free tier available.
Details from balldontlie.io.

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The balldontlie API is provided by BALLDONTLIE (balldontlie.io). Real-time stats for NBA, NFL, MLB, NHL, Soccer, Tennis, Golf, Esports & 20+ leagues. Free tier available.
Yes. The balldontlie 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 balldontlie API requires no authentication, so you can start making requests without signing up.
Yes. The balldontlie API supports CORS, so front-end JavaScript can call it directly.
Yes. The balldontlie API is served over HTTPS, so it's safe to use in production.