GeoJSON is a JSON-based file format that has become popular in a short time. GeoJSON uses the JavaScript Object Notation (JSON) open data standard for storing geographical features as key-value pairs. The files are easily readable, can be created using a simple text editor, and are now common in spatial databases, open data platforms, as well as commercial GIS software. You would use GeoJSON for various types of geospatial vector data, such as points, lines, and polygons. GeoJSON uses either .json or .geojson as the filename extension. This means that a filename doesn't have to be .geojson in order to be a GeoJSON file.