Google Data (GData) Protocol

Google Data, or GData, is a legacy protocol developed by Google to provide a consistent way of reading and writing data on the web. It was originally built on top of the Atom Publishing Protocol (AtomPub) and RSS 2.0, utilizing XML and JSON formats. The protocol was designed to facilitate seamless data exchange across various Google services, such as Google Calendar, Docs, and Contacts.

Over time, Google shifted its focus toward more modern RESTful API architectures and specific Discovery Services. While many original GData APIs have been officially deprecated or replaced by newer versions (like the Google Calendar API v3), the protocol remains a significant part of Google's technological history. It is a proprietary standard developed by Google’s engineers in the United States and continues to be owned and managed by Google LLC under its parent company, Alphabet Inc.