If I log into the mobile app (iOS, Android) will it show i'm online even if I don't have the app open?

Yes, once you've signed in to your Ringotel account in the iOS or Android app, you don't need to keep them open. Please note that your status may change from "Online" to "Away" if you do not open the app for a while (3-10 minutes, depending on the operating system). However, you will still receive calls and new messagesand via the push notifications.