NailKeeper is a free Android app developed by ezebecke that aims to help people quit the habit of nail-biting. The app motivates users to stop biting their nails by tracking their progress and providing tips and tactics to grow their nails faster and better control their impulses.

The app allows users to take photos to track the changes in their nails over time. The before and after images can be compared in video mode to see the progress made in recovering their nails. Users can also set notifications to remind them to take photos and log their progress. The app also features a timer to monitor how much time has passed since they quit and restart it if they relapse.

NailKeeper is an excellent motivational tool for those who want to quit the habit of nail-biting. The app is easy to use and provides useful features to track progress and gain control over impulses.