
Pressure scores, demand, generation mix and alerts for the 10 major U.S. power grids.
GridVigil API is a free Environment API that requires no API key, is served over HTTPS and supports CORS, so it can be called from the browser.
GridVigil's free Developer API: one normalized JSON schema across every grid it tracks, with example requests and responses.
Details from gridvigil.com.

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The GridVigil API is provided by GridVigil (gridvigil.com). GridVigil's free Developer API: one normalized JSON schema across every grid it tracks, with example requests and responses.
Yes. The GridVigil API is listed in the Environment 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 GridVigil API requires no authentication, so you can start making requests without signing up.
Yes. The GridVigil API supports CORS, so front-end JavaScript can call it directly.
Yes. The GridVigil API is served over HTTPS, so it's safe to use in production.