A Google Maps API developer is responsible for creating and maintaining the Google Maps application programming interface (API) for developers. The Google Maps API allows developers to access the functionality of the Google Maps service in their own applications. The API provides a set of tools that can be used to create, edit, and manage map data, as well as to add new features and functionality to the maps themselves. In addition to the core API, there are also a number of supporting libraries and services that can be used to extend the functionality of the maps.