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Productivity · Collaborative documents

Google Docs-style app

Illustrative system design for a collaborative documents app like Google Docs: 6 topics to read, from requirements to deep dives.

Every keystroke is a write.

Illustrative design, not Google Docs’s actual implementation. Arrowbox is not affiliated with Google Docs’s owner. Disclaimer

Start with Rich text Sign in to start readingUpdated 2 Oct 2026

Editor

  • Rich text editingAdvanced · 43 min read · Sign in to read

    A document model under contenteditable: marks, selection, paste and a 200-page doc.

  • Comments and suggestionsIntermediate · 44 min read · Sign in to read

    Threads anchored to text ranges, suggesting mode, and anchors that survive edits.

Sync

  • Live co-editingAdvanced · 46 min read · Sign in to read

    The client side of OT: pending ops, acks, rebasing remote edits, and carets that stay put.

  • Offline and conflictsAdvanced · 45 min read · Sign in to read

    Keep typing on a train: a durable local op queue, merge on reconnect, and honest conflict UI.

Sharing and history

  • Version historyIntermediate · 45 min read · Sign in to read

    Browse named and automatic versions, see who changed what, restore without losing anything.

  • Sharing and permissionsIntermediate · 43 min read · Sign in to read

    Invite people, set roles and link access, and have the open editor react when a role changes.