Not right now. Existence needs an active internet connection, either Wi-Fi or mobile data, to load your account and save any changes. When you're offline, you won't be able to view the platform or make updates.
What if I lose connection in the middle of an entry?
If your connection drops while you're working, your latest changes may not save. Once you're back online, check that your most recent time block, energy rating, or reflection went through, and re-enter it if it's missing.