All dates and times RECEIVED FROM or SENT TO this API are given as Unix epoch timestamps. This is a ‘long’ value representing the number of seconds that have elapsed since January 1, 1970 (midnight UTC/GMT).
An epoch value is represented in seconds.
To convert from Java to epoch, divide the Java time by 1000.
To convert from epoch to Java, multiply the epoch time by 1000.
Epoch Converter has a page with a simple utility for converting quickly between readable dates and epoch timestamps.