:dfn:`ODK-X Cloud Endpoints` are servers that communicate with the ODK-X Android applications. They implement the ODK-X REST Protocol.
There are currently two options for Cloud Endpoints to communicate with ODK-X tools.
- :doc:`sync-endpoint` - Supports the full ODK-X REST Protocol
- :doc:`aggregate-tables-extension` - Previously supported the majority of the ODK-X REST Protocol; however, is no longer supported, please migrate to :doc:`sync-endpoint`.