According to the official website:

The Pomodoro Technique® is a way to get the most out of time management.
Turn time into a valuable ally to accomplish what we want to do and chart
continuous improvement in the way we do it.

1. A simple TODO list. Your data is stored inside LocalStorage of your browser (if it supports LocalStorage). Future versions may provide REAL web backends to sync data to.
2. A Pomodoro timer that follows that Pomodoro workflow. (However) Current version hasn't implemented "interruptions" and "unexpected events" yet.

Visit Tomato's Github Page, and the rest is straightforward.

The UI design is largely inspired by Thingler, and the todo list coding is inspired by Backbone.js's demo app.