Internals
The machinery the other pages hide: what a replica knows, how much it is storing, and what actually goes over the wire - the page to open when you want to check that the efficiency claims are true rather than take them on faith.
Two replicas, measured
Type into either replica, or let the buttons do it, and watch what each one stores and what it would send.
Opening two replicas…
What the numbers mean
The state vector is a replica's complete summary of what it has seen - one entry per author, a few bytes each. It is the whole of what a peer needs in order to compute the exact delta this replica is missing, which is why reconnecting after a long absence costs one small message rather than a full document transfer.
Blocks are the engine's internal unit of storage. Watch the ratio between characters and blocks as you type: a run of consecutive typing collapses into a single block, so a long document typically holds a few dozen blocks rather than one per character. That collapse is the single most important reason collaborative text is affordable at all.