
Get information about countries via a RESTful API.
REST Countries API is a free Geocoding API that requires no API key, is served over HTTPS and supports CORS, so it can be called from the browser.
REST Countries is a country data API: 250+ countries, 90+ fields each with 99.995% uptime.
Details from restcountries.com.

Unified API suite · now live
Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
Cities content & photos API
Rwanda Provences, Districts, Cities, Capital City, Sector, cells, villages and streets
The REST Countries API is provided by REST Countries (restcountries.com). REST Countries is a country data API: 250+ countries, 90+ fields each with 99.995% uptime.
Yes. The REST 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 REST Countries API requires no authentication, so you can start making requests without signing up.
Yes. The REST Countries API supports CORS, so front-end JavaScript can call it directly.
Yes. The REST Countries API is served over HTTPS, so it's safe to use in production.