Products Hangouts Chat API Reference Hangouts Chat Developer Reference Documentation This part of the Hangouts Chat documentation contains reference information for developers who are integrating or extending Hangouts Chat. Message formats documentation REST API documentation Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 3.0 License, and code samples are licensed under the Apache 2.0 License. For details, see our Site Policies. Java is a registered trademark of Oracle and/or its affiliates. Last updated September 4, 2018.