API Découpage Administratif (API Geo) vs GeoJS

Etalab's Découpage Administratif API looks up and cross-references France's administrative hierarchy — communes, EPCIs, départements, and régions — by name, postcode, SIREN, or geographic coordinates, with no API key required. The stored api.gouv.fr/api/geoapi.html link had gone stale, 301-redirecting to a generic data.gouv.fr listing page instead of the live docs; the real service and interactive documentation are hosted at geo.api.gouv.fr. A live Origin-header probe against the real /communes endpoint confirms open CORS, reflecting back whatever Origin is sent.

GeoJS is a free, no-signup IP geolocation lookup that returns country, city, ASN, and timezone data as JSON or JSONP over HTTPS with open CORS. It's built for simple client-side and ChatOps integrations rather than high-volume commercial traffic, and has no paid tier.