Zippopotam.us OverviewPostal Codes and ZIP Codes made easy. Automatic address completion when provided with a country and ZIP / postal code. Over 60 Countries Supported. Learn More: Zippopotam.usFunctionsPostal Code LookupLooks up address information (city, state, etc.) with the provided country and postal code. If the country is not provided, an attempt will be made to determine what it is based off the provided postal code (USA and Canada only).