# URL Format

A URL string always begins with the Parallels Client URL scheme. See the table in the previous section for a scheme supported on a specific platform. If both URL schemes are supported, you can use either one.

The first parameter that you include after the URL scheme is the `Command` parameter. It tells Parallels Client what kind of action should be performed. The available commands are:

* **GetVersion** — Allows to determine on the web server side which Parallels Client version is installed on a user device, or if the Parallels Client is installed at all.
* **LaunchApp** — Creates a connection, authenticates a user, launches a published resource.
* **Get2xa** — Performs the same actions as the LaunchApp command (above), but uses advanced security, which eliminates passing sensitive information (server name, user credentials, published resource info) in the URL itself.
* **LogOff** — Logs off the user from a session on a specified server or from all sessions on all servers.

The `Command` parameter is placed in the URL as shown in the following example:

`tuxclient:///?Command=LaunchApp`

Command options are specified after the command using the ampersand ("&") separator:

`tuxclient:///?Command=LaunchApp&AppID=2360&ConnMode=0 ...`

Note that the `prlclient://` URL scheme uses the same exact format demonstrated here and in all other examples included in this chapter.