CONCEPT Cited by 2 sources

Object-tree document model

An object-tree document model represents a document as a rooted tree of objects, each with a stable ObjectID and a bag of (Property, Value) entries. It's the data-model choice behind the HTML DOM, the Figma file format, every major design tool, and most real-time-collaboration systems over structured content.

The reduction Figma articulates in its 2019 multiplayer post (Source: sources/2019-figma-how-figmas-multiplayer-technology-works):

• Two-level map: Map<ObjectID, Map<Property, Value>>.
• Database-row view: tuples of (ObjectID, Property, Value) — each triple is one editable fact.
• Tree shape: hierarchy of parent → children edges on top of the map (parent-ID property, or a children-list property on the parent).

Figma: root document → page objects → page-content subtrees (presented as the left-panel layers in the editor).

Why this shape matters for collaboration

The model has three load-bearing consequences for any real-time collaboration system built on top of it:

1. Feature velocity compounds on the schema. "Adding new features to Figma usually just means adding new properties to objects." The schema is open-extension — new capabilities don't require data-model migrations, only new property keys. This is why Figma could keep shipping features on the same multiplayer substrate through 2024 without redesigning the sync model.

2. Property-granular conflict resolution. Because state is decomposed to (ObjectID, Property, Value) triples, concurrent edits to different properties of the same object never conflict — they commute trivially. Concurrent edits to the same (ObjectID, Property) are the only coordination point, and they're resolvable with per-property CRDTs like LWW-register.

3. References as first-class edges. Property values can be ObjectIDs — instance → component, auto-layout frame → contained-child, style → shared-style-source. Those property-valued references are what QueryGraph later indexes as the edges of Figma's dependency graph. The 2019 data model is the graph's vertex set.

Compared to sibling data models

Model	Shape	Concurrency story
Linear text	char[]	OT; offsets shift under inserts/deletes
Object tree	Map<ID, Map<Prop, Val>> + parent edges	Per-property CRDTs; references don't break under concurrent edits
JSON doc tree	Nested ordered maps + arrays	Per-path CRDTs (Automerge, Yjs); list-CRDTs for arrays
Relational rows	Table × PK × column	Row-level LWW + FK constraints; real-time usually bolted on

Seen in

• sources/2019-figma-how-figmas-multiplayer-technology-works — explicit articulation of the Map<ObjectID, Map<Property, Value>> reduction and the DOM-analogy framing. The data-model choice the whole multiplayer stack is built on.
• sources/2026-04-21-figma-how-figma-draws-inspiration-from-the-gaming-world — object-tree is the substrate where FigJam connectors, sticky notes, tables, and layout-controlled objects coexist; the post's cross-system connector-oscillation / autosave-overload bug (concepts/interdependent-systems) works precisely because connector state is a property on object nodes whose values depend on the layout of other object nodes — the object-tree shape is what makes that implicit cross-node coupling possible.

Related

• concepts/conflict-free-replicated-data-type — the natural concurrency primitive for per-property updates on this model.
• concepts/write-dependency-graph — Figma's 2024 bidirectional read/write-dep graph over the vertex set this model defines.
• concepts/reachability-based-subscription — per-session subscription model computed over the tree + reference edges.
• concepts/derived-subtree — portions of the object tree can themselves be framework-derived from other sources of truth; Figma Materializer (2026) generalises this as the third reactive graph over the same document model.
• systems/figma-multiplayer-querygraph — production instance.
• systems/figma-parameter-runtime — sibling reactive graph at parameter-binding granularity.
• systems/figma-materializer — sibling reactive graph at derived-subtree granularity.