onlineKring is a free Android app developed by Andi Santosa. It falls under the category of Social & Communication apps. This app allows users to monitor the online status of a specific WhatsApp number for a set duration of 1 to 120 minutes. By processing screenshot images taken every 10 seconds, onlineKring alerts the user through phone ringing or vibration when the monitored person comes online.

onlineKring can be useful in various scenarios, such as monitoring the online status of a seller when the delivered goods are damaged, keeping an eye on a coworker who has a lot of pending work, checking if a schoolmate is contributing to a group assignment, tracking a business partner's online presence when a debt is due, or even monitoring a child who has started college in another city.

To use onlineKring, users need an Android phone with version 5 to 9, a valid WhatsApp number already installed, and the WhatsApp theme set to "Light" and disappearing messages turned off.

The app requires a few system permissions including view network connections, full network access, control vibration, and preventing the device from sleeping. Upon first run, onlineKring asks for permission to capture everything displayed on the screen, which can be granted by ticking the "Don't show again" option and pressing "Start Now".

While onlineKring is running, it occupies the screen time continuously and does not allow any other foreground app to run simultaneously. Users should avoid pressing the "Send" button if they see the string "hh:mm:ss" in the message body, as it will send that string to the monitored person. To exit the app, users can simply press the back key three times in a row. The app will also exit by itself once the set time duration is finished. If users find the current duration insufficient, they can rerun the app from the beginning at any time after exiting it.