When sending data to the server (PUT, POST, PATCH) set Content-Type header to application/json.
Likewise, when retrieving data from the server set Accept header to application/json.
The server returns all dates in UTC ISO format: yyyy-MM-ddThh:mm:ssZ
This is the example of the typical implementation of the translation support in client's CMS system, using the Stream.API. Both plug-ins for WordPress and Drupal, available for free at our Download section, are designed right according to this diagram.