Project Engine Professional and Enterprise editions are priced based on the number of users that can be simultaneously connected to the server. The server will release a license when a client has been inactive for 5 minutes.
Project Engine Personal
Project Engine Personal is completely free and can be used as a single user project planning and tracking system. No license key is required.
Project Engine Professional
The Professional edition is designed for smaller businesses and enterprises. It offers a subset of the features in the Enterprise edition. The Professional edition is an option when working mainly at one location.
Project Engine Enterprise
Project Engine Enterprise edition is the full version designed to be suitable for an enterprise. The Enterprise edition is recommended when the team is distributed on many locations.