Project context and scope

A full-stack collaborative canvas system with Redis-coordinated backend replicas, PostgreSQL-owned revisions, transient previews, shared undo/redo, access control, presence, and Drive-style organization.

LiveBoard is a collaborative whiteboard application built around a React/SVG editor, horizontally scalable FastAPI backend replicas, PostgreSQL-owned durable state, Redis-coordinated ephemeral state, and WebSocket collaboration rooms. The application supports account sessions, owned and shared canvases, nested drag-and-drop folders, arbitrary sibling reordering, search and owner filtering for shared boards, invite and removal flows, realtime shape editing, presence cursors, infinite-canvas navigation, grouping, nested grouping, z-ordering, text editing with whole-object style and alignment controls, opacity, stroke width, rotation, multi-selection transforms, rate-limit recovery, and shared undo/redo. The central architectural choice is that durable canvas state, revision ordering, and undo/redo history remain owned by PostgreSQL and the backend, while Redis is used only for cross-server fanout, presence, invalidation, and counters. User actions are represented as typed operations, applied under an authoritative canvas revision, inverted against locked state, and broadcast to connected editors. This paper describes the product feature set, data model, operation algebra, collaboration protocol, distributed runtime, access lifecycle, frontend interaction model, and operational tradeoffs in sufficient detail to reconstruct the system.

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