Trigger, Action, Variable Reward, Investment. Four steps, and suddenly your users can't stop opening the app.
About the book
Nir Eyal's Hook Model explains how products like Instagram and Twitter engineer habits, cycling users through an external or internal trigger, a simple action, an unpredictable reward, and a small investment that loads the next trigger. The book is as much about ethics as mechanics — it pushes readers to run the loop through a manipulation matrix before shipping it, distinguishing habit formation that serves users from the kind that just exploits them. It's a design pattern, and like any design pattern it can be used well or badly.
Best used for
—Designing engagement loops and notification strategies that bring users back
—Building streaks or progress systems that compound over sessions
—Running a proposed feature through an ethics check before shipping a habit-forming loop
“Extremely valuable book for anyone building products designed to engage people frequently.”
— Otis Chandler, Goodreads
Install this skill
Run this command in your terminal. The skill will be available in all your Claude Code projects.