Web maps created on ArcGIS Online are configured using JSON format. Esri has created the Web Map Data JSON specification for this configuration. This means you are not always required to use ArcGIS Online to create web maps.
I starred Rene Rubalcava’s webmaputils repository on GitHub on October 16, 2013. Webmaputils was Rene’s framework for creating web maps that conform to Esri’s web map data specification. While development has apparently ceased, webmaputils is still a great resource for understanding the process of creating web maps to the Esri specification.
“Why I starred” is a series of articles describing projects I star on GitHub and why I found them interesting. My hope is that you’ll find them interesting as well.