While the Orthanc viewer plugin and the Osimis BASIC viewer plugin are free of charge, the Osimis PRO Viewer isn't.
The main difference between the BASIC and the PRO viewer is that the PRO viewer is CE-marked and that it offers the Liveshare feature.
Osimis provides the PRO viewer with support, which is the only way for us to guarantee CE-marking. The cost of this support is 624 EUR Excl. VAT per month per organisation using the code, disregarding of the number implementations.