
Country-related data like currencies, languages, flags, regions+subregions and bordering countries.
Graph Countries API is a free Geocoding API that requires no API key, is served over HTTPS and has unconfirmed CORS support.
An easy to use GraphQL API to query country-related data for free and without restrictions
Details from github.com.

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Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
The Graph Countries API is provided by lennertVanSever (github.com). An easy to use GraphQL API to query country-related data for free and without restrictions
Yes. The Graph Countries API is listed in the Geocoding 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 Graph Countries API requires no authentication, so you can start making requests without signing up.
CORS support for the Graph Countries API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The Graph Countries API is served over HTTPS, so it's safe to use in production.