That depends. Our pricing is based on the number of PointOS Point of Sale Software clients connected to the database, at one time. PointOS uses SQL Server Express, which in itself does not count as a client. Therefore, if you do not purchase a client for the backoffice, you can still run the server off of it. However, if you wish to check sales or do setup from the backoffice computer, you will need to either purchase another PointOS client or simply shut down a PointOS client on another computer. Basically, if you want to run PointOS on the backoffice only after hours or when one of your other stations is down, you will not need to purchase a client.