In the REST API, process variables are represented by JSON objects of the following form:

{
  "type": "String",
  "value": "Some value",
  "valueInfo": {}

}

The REST API supports the Value Types supported by the process engine.

Capitalization of Type Names

In the REST API, the type names start with a capital letter, i.e., String instead of string.

Serialized and Deserialized Object Values

Object Values are instances of (non primitive) Java types. When working with the REST API, it is generally advisable to work with the serialized value of a variable. In that case the value is retrieved from the database and directly returned in the http response. If the client you are building is not a Java Applications by itself, make sure you use a text-based serialization dataformat (such as XML or JSON).

Serialize Variables of type Object in REST API

In the REST API, process variables of type Object can be serialized in JSON or XML format.

Serializing Object into JSON format:

    {
       "variables": {
          "aVariable": {
             "value": "{\"somekey\": \"somevalue\"}",
             "type": "Object",
             "valueInfo": {
                "objectTypeName": "com.camunda.SomeClass",
                "serializationDataFormat": "application/json"
             }
          }
       }
    }

Serializing Object into XML format:

    {
       "variables": {
          "aVariable": {
             "value": "<somekey>somevalue</somekey>",
             "type": "Object",
             "valueInfo": {
                "objectTypeName": "com.camunda.SomeClass",
                "serializationDataFormat": "application/xml"
             }
          }
       }
    }