OpenStreetMap vs PostalCodes

The core OpenStreetMap API serves and edits the raw map database underlying OSM — nodes, ways, and relations — over HTTPS at api.openstreetmap.org. Reading map data requires no authentication at all, while creating or modifying data requires an OAuth 2.0 token tied to an OSM account (the older Basic Auth/OAuth 1.0a login methods were retired in June 2024). It's a general-purpose data API rather than a geocoding service specifically — OSM points address-lookup users to the separate Nominatim service, and bulk-read users to Overpass.

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.