JSON is designed to be understood by humans and machines alike. JavaScript data objects are easily generated from Python dictionaries, as they use the same key value structure and curly bracket notation. Python contains a built-in library for generating JSON (the json module), and web frameworks such as Flask also include code for generating JSON responses.

Multiple JSON standards exist for geospatial data, including GeoJSON and Esri JSON. Within this chapter, the REST API will use the GeoJSON format to respond to requests.