The REST API uses the default date format yyyy-MM-dd'T'HH:mm:ss.SSSZ, which represents a date with milliseconds and timezone information, e.g., 2016-01-25T13:33:42.165+0100.

Custom Date Format

A custom date format can be configured in the web.xml file of the REST API. To do so, the ServletContextListener CustomJacksonDateFormatListener has to be added. The custom date format can be specified by the context parameter org.camunda.bpm.engine.rest.jackson.dateFormat.

For example, if the date format should not contain milliseconds and timezone information (yyyy-MM-dd'T'HH:mm:ss) the following configuration can be used.

To achieve this, you can edit the WEB-INF/web.xml file as follows:

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

  <!-- ... -->

  <listener>
    <listener-class>
      org.camunda.bpm.engine.rest.CustomJacksonDateFormatListener
    </listener-class>
  </listener>

  <context-param>
    <param-name>org.camunda.bpm.engine.rest.jackson.dateFormat</param-name>
    <param-value>yyyy-MM-dd'T'HH:mm:ss</param-value>
  </context-param>

  <!-- ... -->
</web-app>

With this configuration the REST API will return dates with millisecond precision and timezone information. Also, new dates with milliseconds and timezone information can be submitted to the REST API without losing these details.