All subscriptions of Mydoma include the base version of the Mydoma Visualizer. The pro version however includes a number of upgrades for an additional monthly cost of $30 USD on top of your Mydoma subscription.
Additional cost of $30 USD/MO
You can move from one pricing tier to another at any time or upgrade from a monthly to annual plan. Since annual plans are prepaid for the year, changing to a monthly should be done only at the end of your year subscription.