Cartes.io vs PostalCodes

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.

Postalcodes.info is a free postal-code reference for 123 countries and more than 1.8 million records. No key is needed. The JSON endpoint /api/v1/postal-code/{country}/{code} returns the place name, region and coordinates for one code. Per-country exports come as CSV, JSON or XLSX. The JSON API sends Access-Control-Allow-Origin: *, so a browser can call it directly. The /search autocomplete endpoint does not send that header.