A live reading session looks simple: several people read the same book and see each other. Keeping that true when connections drop, tabs sleep and devices differ takes more care than it looks.
The problem
Every reader emits a stream of small updates. Most of them are only useful for a moment, so the system must favour the latest position over a perfect history.
Our approach
- Positions are last-write-wins and tiny.
- Comments are durable and anchored to the text.
- A reconnecting reader catches up from the current state.