Upside-down database: real-time sync and offline work with Swarm.js

Sync is a cornerstone technology of collaborative apps. Given that an average user has multiple devices, single-user apps need sync too.
Swarm is a minimalistic sync-centric database built with Conflict-free Replicated Data Types (CRDTs). It works in a browser, syncs data in real time, merges concurrent changes and, importantly, offline replicas are writable.
The talk covers: (1) how it works and (2) how to use the thing.