Real-time, offline and sync
Comes up in: Frontend system design
This concept is being written. It gets the full five steps — explanation, predict, interview angle, practice with tests, and review cards. Here is exactly what it will cover, so you can study it elsewhere in the meantime.
What it covers
- choosing polling/SSE/WebSocket
- offline-first with IndexedDB + service worker
- sync queues
- conflict resolution (last-write-wins, version vectors, OT and CRDTs at a concept level)
- reconnection
Words you will know
What you will practise
- design offline editing for notes
Interview questions this answers
- How would you make an app work offline and sync later?
- CRDT vs operational transformation: what is the difference at a high level?