
Covid-19 data for the US.
Covid Tracking Project API is a free Health API that requires no API key, is served over HTTPS and does not support CORS, so it should be called from a server.
The COVID Tracking Project collects and publishes the most complete testing data available for US states and territories.
Details from covidtracking.com.

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Maps, datasets, applications and more in the context of COVID-19
The Covid Tracking Project API is provided by The COVID Tracking Project (covidtracking.com). The COVID Tracking Project collects and publishes the most complete testing data available for US states and territories.
Yes. The Covid Tracking Project API is listed in the Health 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 Covid Tracking Project API requires no authentication, so you can start making requests without signing up.
Not directly. The Covid Tracking Project API does not allow CORS, so call it from a server, serverless function or proxy instead of front-end JavaScript.
Yes. The Covid Tracking Project API is served over HTTPS, so it's safe to use in production.