A request XML packet retrieving the list of all Web applications from the Application pool of the specified client includes the get_packages_list_by_client operation node:
<packet version="1.4.2.0">
<siteapp>
<get_packages_list_by_client>
...
</get_packages_list_by_client>
</siteapp>
</packet>
The get_packages_list_by_client node has the following graphical representation:

Remarks
You can retrieve lists of Web applications of multiple clients in a single packet. Add as many get_packages_list_by_client operations as the number of clients which lists are to be viewed.
<siteapp>
<get_packages_list_by_client>
¡
</get_packages_list_by_client>
...
<get_packages_list_by_client>
¡
</get_packages_list_by_client>
</siteapp>