Borrow Mode

Purpose

Borrow Mode is an Android-first phone handoff app that restricts a device to one selected app before lending it to someone. The borrower can use the allowed app, while leaving it redirects them back until the owner authenticates, the timer ends, or the screen turns off.

Features

1. Installed app picker for choosing exactly which app the borrower can use.
2. AccessibilityService-based guard that detects when the borrower leaves the allowed app and redirects them back.
3. Foreground service notification for session visibility and owner-controlled exit.
4. Biometric and device credential authentication using the phone’s existing lock method.
5. Optional timer-based auto-exit for short handoff sessions.
6. Screen-off exit behavior so the session can end safely when the phone is locked.
7. In-app onboarding for accessibility, notification, and battery optimization permissions.

Lesson Learnt

1. Permission-heavy apps need clear onboarding because one denied permission can change the whole reliability of the borrowing session.