The US County Database is a comprehensive list with all counties names, codes, states, etc. All data can be accessed and manipulated via GraphQL and REST APIs. Users can also copy the list of US county names and edit the data.
The US Zip Code Database provides the postal codes for all US cities and counties. You can fetch data connecting to a ready-to-use API or download the database. The Zip Code API is available under GraphQL and REST protocols and programming languages like Javascript, PHP, NodeJS, Swift, Dart, etc.