Cartes.io vs API Découpage Administratif (API Geo)

Cartes.io is an open-source platform for creating and sharing custom maps with markers, letting anyone plot points, GeoJSON shapes, and metadata without running their own server. Reading public maps and markers needs no signup — write access is optional and controlled per map, either open to anyone or gated behind a token issued when the map or marker is created. The API returns JSON by default and GeoJSON on request, and the project ships official Python and NPM packages alongside its hosted instance at cartes.io.

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.