Altairis, also known as Altair Communications, is a Czech IT company. PaleHorse is their mailing list management system. It allows users to retrieve information about a mailing list, add or remove subscribers, determine whether someone is a subscriber, send a message to a mailing list, and so on. These functions are accessible programmatically using SOAP calls issued in XML format.
Although PaleHorse and its documentation are provided in English, the Altairis website itself is offered exclusively in Czech.