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Fitbit SDK Guides

These resources will help you understand how to use each element of the Fitbit SDK. You’ll find guides for:

App Architecture

Explore the basic building blocks of a Fitbit app and how they fit together

Command Line Interface

Learn how to create, build and screenshot projects using the CLI.


Learn how the companion API enhances Fitbit apps with an additional JavaScript runtime environment

File System

Learn how the File System API allows developers to read and write files on the Fitbit device


If you want to understand some of the terminology used in the guides, please read our Glossary


Learn how to migrate your application between SDK versions


Apps must be granted permissions by the user in order to use specific APIs


Learn how the Sensor APIs connect developers with the hardware sensors embedded in Fitbit devices

User Interface

Learn how to build UI using SVG, CSS and JavaScript.

Clock Faces

Learn how the Clock API handles tick events with the correct precision and timing


Learn how to send and receive data or transfer files between Fitbit devices and mobile devices

Design Guidelines

Design clocks and apps with our system of visual styles and components.


Understand how to access the physical location of a device using GPS


Understand how to localize your apps and clocks.

Multiple Devices

Learn how to build for multiple device targets simultaneously


Learn how to publish your apps and clocks to the Fitbit App Gallery


Learn how to create a settings definition file so you can make your app configurable by users