To retrieve the Plesk license key currently installed on a server, use the get operation with the key parameter specified.

A request XML packet getting license key contains the key node nested within the get operational node:

<packet>
    <server>
        <get>
            <key/>
        </get>
    </server>
</packet>

An XML response packet received from the server can look as follows:

<packet>
    <server>
        <get>
            <result>
                <status>ok</status>
                <key>
                    <property>
                        <name>plesk_key_id</name>
                        <value>plsk.00000000.0000</value>
                    </property>
                    <property>
                        <name>product_version</name>
                        <value>12.0</value>
                    </property>
                    ...
                </key>
            </result>
        </get>
    </server>
</packet>

For details of a response structure, refer to the Getting Server Information: License Key section.