We have several customers utilizing a cloud server.  Keep in mind that a cloud server is just a server that is hosted in a data center rather than at your location.   As such, you can use a WAN setup ( http://support.1000years.com/kb/a32/wan-remote-access.aspx ) using the cloud server to store the Atrex data. The downside to using a cloud server is that Atrex is data heavy and ALL of your Atrex users will feel the lag between the workstations and the server.

A couple of other users are using a cloud server to host the data and are then using remote terminal sessions to access Atrex and other applications running on the server. This is more expensive as you need a more powerful server to handle the terminal sessions, but allows Atrex to run much faster as only the screen, keyboard, and mouse information is being sent back and forth to the user.

And of course, if you host your own internal server, you can configure Atrex for WAN using your own server to feed the data. This allows the users inside your network fast access, and only the remote users feel the lag between their location and your server.

Lastly, keep in mind that we've done a lot of work in the recent versions of Atrex (18+) to make WAN access faster such as improving the performance of the lookup cache loading, batch saves of transaction items instead of one by one inserts, and use of local cached result sets when possible.