This document delves into the wire protocol used for synchronizing content between two Fossil repositories. Synchronization involves sharing artifacts so that all repositories have the same content. Interestingly, Fossil’s data model aligns with Conflict-Free Replicated Datatypes (CRDTs) even though the terminology predates the academic literature on the topic. The protocol operates over HTTP, with support for HTTPS and SSH transports. Different types of cards, like login and file cards, are utilized during synchronization. The protocol ensures data integrity and privacy while efficiently transferring artifacts. In the end, Fossil delivers a reliable and robust synchronization process.
https://fossil-scm.org/home/doc/trunk/www/sync.wiki