Can I use Ellipsus offline?

It is not currently possible to open or edit documents or drafts offline, as doing so will prevent you from syncing or saving, but offline functionality is a high priority for us. 

Ellipsus began as a collaborative web app because real-time collaboration is much harder to add later than it is to build from the beginning (this is why a lot of offline tools do not include collaboration retroactively). Offline mode is a big technical initiative, especially for a tool built around syncing and collaboration.