IP geolocation with ChatOps integration.
GeoJS 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/JSON/JSONP GeoIP API
Details from geojs.io.

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.
The GeoJS API is provided by GeoJS (geojs.io). REST/JSON/JSONP GeoIP API
Yes. The GeoJS 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 GeoJS API requires no authentication, so you can start making requests without signing up.
Yes. The GeoJS API supports CORS, so front-end JavaScript can call it directly.
Yes. The GeoJS API is served over HTTPS, so it's safe to use in production.