Research on Fitbit Flex

This document is a working document with information found from our own reverse engineering since 2014 and other information gathered on the web and mailing lists.

It is important to understand that much information in here remains uncertain with quite possibly many errors.

If you use information from this document, use it responsibly and at your own risk.

This document has been sent to Fitbit in November 2016, and they have not expressed any issue with its publication.

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Technical report on our research on the Fitbit Flex tracker.