4D Workflow Backend Architecture & Sync

Bi-directional synchronization between Notion and Google Calendar requires a backend orchestration layer that exposes a REST API surface, enforcing Notion as the single source of truth while mapping task lifecycle updates to calendar events.

Optimistic UI in backend task synchronization uses an orchestration strategy to apply immediate local state updates, ensuring cross-platform consistency and handling conflicts while a SyncWorker polls external变动 to sync final backend states.

Environment-based credentials are required to authenticate the Notion and Google Calendar API services, allowing the backend to securely fetch tasks, manage calendar events, and expose protected REST API endpoints.

Ensuring cross-platform consistency for task management involves enforcing Notion as the single source of truth, using a SyncOrchestrator for optimistic updates, and relying on a polling SyncWorker to detect external changes across platforms.

A polling mechanism can detect external task changes in Google Calendar by utilizing a SyncWorker that continuously checks for external变动, ensuring the local interface and backend state remain synchronized without relying on direct webhooks.

Notion acts as the single source of truth for calendar integration to prevent data conflicts, ensuring all task lifecycle changes originate from the Notion database before synchronizing to Google Calendar events via the REST API.