Skip to content

Google Docs — Notes#

Functional#

  • Concurrent editing with sub-second sync.
  • Cursor + selection presence.
  • Comments, suggesting, version history.
  • Offline mode + reconciliation.
  • Sharing, link tokens, ACLs.

Non-functional#

  • p99 op echo < 200 ms.
  • 100+ concurrent editors per doc.
  • 99.99% uptime.

Trade-offs#

  • OT vs CRDT: OT mature with central server; CRDT decentralizable + offline-friendly.
  • Per-doc serialization simplifies correctness; failover challenge.
  • Storage: op log → periodic snapshots to bound replay cost.

Refs#

  • Google Wave / Docs OT papers.
  • Yjs / Automerge / RGA papers.
  • ByteByteGo "Design Google Docs".