Table 1.

The classification framework of app features.

Category and feature		Definition	Source of definition
Self-tracking
	Use history and visualization	Provides a summary of mobile phone use history and a visualization (ie, mobile phone use history, notification, most used app, and unlocked count) daily, weekly, or monthly	Monge Roffarello and de Russis [13], Lyngs et al [21], and the authors of this paper
Social tracking
	Social sharing of mobile phone use	Shares progress	Lyngs et al [21]
	Global comparison	Provides information about the global use average and compares it with the user’s mobile phone use	The authors of this paper
Goal setting
	Set goal or group goal	Allows users to set limits on mobile phone use or desired focus time. In addition, users can create groups within the app to set use limits for specific apps, such as social media apps	Lyngs et al [21] and the authors of this paper
	Set activity or interest goal	Allows users to set goals for hobbies or activities	Lyngs et al [21]
	Goal warning	Sends use alert (a reminder when the set limit is approaching)	The authors of this paper
Blocking
	Spontaneous	Allows users to lock the mobile phone quickly (duration can be chosen), lock the mobile phone (until the user chooses to unlock it), or immediately disconnect via 1-click access to the widget	The authors of this paper
	Scheduled	Schedules or sets rules to silence notifications, alerts, and calls; schedules blocklist; schedules off time; disconnects from distracting apps; automatically enters “do not disturb” mode; and automatically locks apps (a password or PINa must be entered to continue accessing apps, modify the active app block profile, or uninstall the app used to reduce mobile phone use and MMPUb)	The authors of this paper
Gamification
	Gain or loss points	Incorporates engaging features to motivate users to reduce mobile phone use. One such feature is the points system, where users can earn rewards by staying focused and lose points for excessive mobile phone use	Lyngs et al [21]
	Real-world reward	Plants trees (ie, Forest app)	Lyngs et al [21]
Simplification		Changes the interface display from color to black and white to make for a less engaging screen (ie, grayscale mode); other authors call it minimization [21]	The authors of this paper
Assessment		Assesses the level of addiction to help users understand their current situation	The authors of this paper

^aPIN: personal identification number.

^bMMPU: maladaptive mobile phone use.